err.no Git - linux-2.6/blob - drivers/acpi/processor_idle.c

   1 /*
   2  * processor_idle - idle state submodule to the ACPI processor driver
   3  *
   4  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   5  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   6  *  Copyright (C) 2004, 2005 Dominik Brodowski <linux@brodo.de>
   7  *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
   8  *                      - Added processor hotplug support
   9  *  Copyright (C) 2005  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
  10  *                      - Added support for C3 on SMP
  11  *
  12  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  13  *
  14  *  This program is free software; you can redistribute it and/or modify
  15  *  it under the terms of the GNU General Public License as published by
  16  *  the Free Software Foundation; either version 2 of the License, or (at
  17  *  your option) any later version.
  18  *
  19  *  This program is distributed in the hope that it will be useful, but
  20  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  21  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  22  *  General Public License for more details.
  23  *
  24  *  You should have received a copy of the GNU General Public License along
  25  *  with this program; if not, write to the Free Software Foundation, Inc.,
  26  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  27  *
  28  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  29  */
  30
  31 #include <linux/kernel.h>
  32 #include <linux/module.h>
  33 #include <linux/init.h>
  34 #include <linux/cpufreq.h>
  35 #include <linux/proc_fs.h>
  36 #include <linux/seq_file.h>
  37 #include <linux/acpi.h>
  38 #include <linux/dmi.h>
  39 #include <linux/moduleparam.h>
  40 #include <linux/sched.h>        /* need_resched() */
  41 #include <linux/pm_qos_params.h>
  42 #include <linux/clockchips.h>
  43 #include <linux/cpuidle.h>
  44
  45 /*
  46  * Include the apic definitions for x86 to have the APIC timer related defines
  47  * available also for UP (on SMP it gets magically included via linux/smp.h).
  48  * asm/acpi.h is not an option, as it would require more include magic. Also
  49  * creating an empty asm-ia64/apic.h would just trade pest vs. cholera.
  50  */
  51 #ifdef CONFIG_X86
  52 #include <asm/apic.h>
  53 #endif
  54
  55 #include <asm/io.h>
  56 #include <asm/uaccess.h>
  57
  58 #include <acpi/acpi_bus.h>
  59 #include <acpi/processor.h>
  60
  61 #define ACPI_PROCESSOR_COMPONENT        0x01000000
  62 #define ACPI_PROCESSOR_CLASS            "processor"
  63 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
  64 ACPI_MODULE_NAME("processor_idle");
  65 #define ACPI_PROCESSOR_FILE_POWER       "power"
  66 #define US_TO_PM_TIMER_TICKS(t)         ((t * (PM_TIMER_FREQUENCY/1000)) / 1000)
  67 #define PM_TIMER_TICK_NS                (1000000000ULL/PM_TIMER_FREQUENCY)
  68 #ifndef CONFIG_CPU_IDLE
  69 #define C2_OVERHEAD                     4       /* 1us (3.579 ticks per us) */
  70 #define C3_OVERHEAD                     4       /* 1us (3.579 ticks per us) */
  71 static void (*pm_idle_save) (void) __read_mostly;
  72 #else
  73 #define C2_OVERHEAD                     1       /* 1us */
  74 #define C3_OVERHEAD                     1       /* 1us */
  75 #endif
  76 #define PM_TIMER_TICKS_TO_US(p)         (((p) * 1000)/(PM_TIMER_FREQUENCY/1000))
  77
  78 static unsigned int max_cstate __read_mostly = ACPI_PROCESSOR_MAX_POWER;
  79 #ifdef CONFIG_CPU_IDLE
  80 module_param(max_cstate, uint, 0000);
  81 #else
  82 module_param(max_cstate, uint, 0644);
  83 #endif
  84 static unsigned int nocst __read_mostly;
  85 module_param(nocst, uint, 0000);
  86
  87 #ifndef CONFIG_CPU_IDLE
  88 /*
  89  * bm_history -- bit-mask with a bit per jiffy of bus-master activity
  90  * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms
  91  * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms
  92  * 100 HZ: 0x0000000F: 4 jiffies = 40ms
  93  * reduce history for more aggressive entry into C3
  94  */
  95 static unsigned int bm_history __read_mostly =
  96     (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1));
  97 module_param(bm_history, uint, 0644);
  98
  99 static int acpi_processor_set_power_policy(struct acpi_processor *pr);
 100
 101 #else   /* CONFIG_CPU_IDLE */
 102 static unsigned int latency_factor __read_mostly = 2;
 103 module_param(latency_factor, uint, 0644);
 104 #endif
 105
 106 /*
 107  * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
 108  * For now disable this. Probably a bug somewhere else.
 109  *
 110  * To skip this limit, boot/load with a large max_cstate limit.
 111  */
 112 static int set_max_cstate(const struct dmi_system_id *id)
 113 {
 114         if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
 115                 return 0;
 116
 117         printk(KERN_NOTICE PREFIX "%s detected - limiting to C%ld max_cstate."
 118                " Override with \"processor.max_cstate=%d\"\n", id->ident,
 119                (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1);
 120
 121         max_cstate = (long)id->driver_data;
 122
 123         return 0;
 124 }
 125
 126 /* Actually this shouldn't be __cpuinitdata, would be better to fix the
 127    callers to only run once -AK */
 128 static struct dmi_system_id __cpuinitdata processor_power_dmi_table[] = {
 129         { set_max_cstate, "IBM ThinkPad R40e", {
 130           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 131           DMI_MATCH(DMI_BIOS_VERSION,"1SET70WW")}, (void *)1},
 132         { set_max_cstate, "IBM ThinkPad R40e", {
 133           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 134           DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW")}, (void *)1},
 135         { set_max_cstate, "IBM ThinkPad R40e", {
 136           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 137           DMI_MATCH(DMI_BIOS_VERSION,"1SET43WW") }, (void*)1},
 138         { set_max_cstate, "IBM ThinkPad R40e", {
 139           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 140           DMI_MATCH(DMI_BIOS_VERSION,"1SET45WW") }, (void*)1},
 141         { set_max_cstate, "IBM ThinkPad R40e", {
 142           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 143           DMI_MATCH(DMI_BIOS_VERSION,"1SET47WW") }, (void*)1},
 144         { set_max_cstate, "IBM ThinkPad R40e", {
 145           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 146           DMI_MATCH(DMI_BIOS_VERSION,"1SET50WW") }, (void*)1},
 147         { set_max_cstate, "IBM ThinkPad R40e", {
 148           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 149           DMI_MATCH(DMI_BIOS_VERSION,"1SET52WW") }, (void*)1},
 150         { set_max_cstate, "IBM ThinkPad R40e", {
 151           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 152           DMI_MATCH(DMI_BIOS_VERSION,"1SET55WW") }, (void*)1},
 153         { set_max_cstate, "IBM ThinkPad R40e", {
 154           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 155           DMI_MATCH(DMI_BIOS_VERSION,"1SET56WW") }, (void*)1},
 156         { set_max_cstate, "IBM ThinkPad R40e", {
 157           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 158           DMI_MATCH(DMI_BIOS_VERSION,"1SET59WW") }, (void*)1},
 159         { set_max_cstate, "IBM ThinkPad R40e", {
 160           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 161           DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW") }, (void*)1},
 162         { set_max_cstate, "IBM ThinkPad R40e", {
 163           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 164           DMI_MATCH(DMI_BIOS_VERSION,"1SET61WW") }, (void*)1},
 165         { set_max_cstate, "IBM ThinkPad R40e", {
 166           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 167           DMI_MATCH(DMI_BIOS_VERSION,"1SET62WW") }, (void*)1},
 168         { set_max_cstate, "IBM ThinkPad R40e", {
 169           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 170           DMI_MATCH(DMI_BIOS_VERSION,"1SET64WW") }, (void*)1},
 171         { set_max_cstate, "IBM ThinkPad R40e", {
 172           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 173           DMI_MATCH(DMI_BIOS_VERSION,"1SET65WW") }, (void*)1},
 174         { set_max_cstate, "IBM ThinkPad R40e", {
 175           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 176           DMI_MATCH(DMI_BIOS_VERSION,"1SET68WW") }, (void*)1},
 177         { set_max_cstate, "Medion 41700", {
 178           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
 179           DMI_MATCH(DMI_BIOS_VERSION,"R01-A1J")}, (void *)1},
 180         { set_max_cstate, "Clevo 5600D", {
 181           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
 182           DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")},
 183          (void *)2},
 184         {},
 185 };
 186
 187 static inline u32 ticks_elapsed(u32 t1, u32 t2)
 188 {
 189         if (t2 >= t1)
 190                 return (t2 - t1);
 191         else if (!(acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER))
 192                 return (((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
 193         else
 194                 return ((0xFFFFFFFF - t1) + t2);
 195 }
 196
 197 static inline u32 ticks_elapsed_in_us(u32 t1, u32 t2)
 198 {
 199         if (t2 >= t1)
 200                 return PM_TIMER_TICKS_TO_US(t2 - t1);
 201         else if (!(acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER))
 202                 return PM_TIMER_TICKS_TO_US(((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
 203         else
 204                 return PM_TIMER_TICKS_TO_US((0xFFFFFFFF - t1) + t2);
 205 }
 206
 207 /*
 208  * Callers should disable interrupts before the call and enable
 209  * interrupts after return.
 210  */
 211 static void acpi_safe_halt(void)
 212 {
 213         current_thread_info()->status &= ~TS_POLLING;
 214         /*
 215          * TS_POLLING-cleared state must be visible before we
 216          * test NEED_RESCHED:
 217          */
 218         smp_mb();
 219         if (!need_resched()) {
 220                 safe_halt();
 221                 local_irq_disable();
 222         }
 223         current_thread_info()->status |= TS_POLLING;
 224 }
 225
 226 #ifndef CONFIG_CPU_IDLE
 227
 228 static void
 229 acpi_processor_power_activate(struct acpi_processor *pr,
 230                               struct acpi_processor_cx *new)
 231 {
 232         struct acpi_processor_cx *old;
 233
 234         if (!pr || !new)
 235                 return;
 236
 237         old = pr->power.state;
 238
 239         if (old)
 240                 old->promotion.count = 0;
 241         new->demotion.count = 0;
 242
 243         /* Cleanup from old state. */
 244         if (old) {
 245                 switch (old->type) {
 246                 case ACPI_STATE_C3:
 247                         /* Disable bus master reload */
 248                         if (new->type != ACPI_STATE_C3 && pr->flags.bm_check)
 249                                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
 250                         break;
 251                 }
 252         }
 253
 254         /* Prepare to use new state. */
 255         switch (new->type) {
 256         case ACPI_STATE_C3:
 257                 /* Enable bus master reload */
 258                 if (old->type != ACPI_STATE_C3 && pr->flags.bm_check)
 259                         acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
 260                 break;
 261         }
 262
 263         pr->power.state = new;
 264
 265         return;
 266 }
 267
 268 static atomic_t c3_cpu_count;
 269
 270 /* Common C-state entry for C2, C3, .. */
 271 static void acpi_cstate_enter(struct acpi_processor_cx *cstate)
 272 {
 273         if (cstate->entry_method == ACPI_CSTATE_FFH) {
 274                 /* Call into architectural FFH based C-state */
 275                 acpi_processor_ffh_cstate_enter(cstate);
 276         } else {
 277                 int unused;
 278                 /* IO port based C-state */
 279                 inb(cstate->address);
 280                 /* Dummy wait op - must do something useless after P_LVL2 read
 281                    because chipsets cannot guarantee that STPCLK# signal
 282                    gets asserted in time to freeze execution properly. */
 283                 unused = inl(acpi_gbl_FADT.xpm_timer_block.address);
 284         }
 285 }
 286 #endif /* !CONFIG_CPU_IDLE */
 287
 288 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 289
 290 /*
 291  * Some BIOS implementations switch to C3 in the published C2 state.
 292  * This seems to be a common problem on AMD boxen, but other vendors
 293  * are affected too. We pick the most conservative approach: we assume
 294  * that the local APIC stops in both C2 and C3.
 295  */
 296 static void acpi_timer_check_state(int state, struct acpi_processor *pr,
 297                                    struct acpi_processor_cx *cx)
 298 {
 299         struct acpi_processor_power *pwr = &pr->power;
 300         u8 type = local_apic_timer_c2_ok ? ACPI_STATE_C3 : ACPI_STATE_C2;
 301
 302         /*
 303          * Check, if one of the previous states already marked the lapic
 304          * unstable
 305          */
 306         if (pwr->timer_broadcast_on_state < state)
 307                 return;
 308
 309         if (cx->type >= type)
 310                 pr->power.timer_broadcast_on_state = state;
 311 }
 312
 313 static void acpi_propagate_timer_broadcast(struct acpi_processor *pr)
 314 {
 315         unsigned long reason;
 316
 317         reason = pr->power.timer_broadcast_on_state < INT_MAX ?
 318                 CLOCK_EVT_NOTIFY_BROADCAST_ON : CLOCK_EVT_NOTIFY_BROADCAST_OFF;
 319
 320         clockevents_notify(reason, &pr->id);
 321 }
 322
 323 /* Power(C) State timer broadcast control */
 324 static void acpi_state_timer_broadcast(struct acpi_processor *pr,
 325                                        struct acpi_processor_cx *cx,
 326                                        int broadcast)
 327 {
 328         int state = cx - pr->power.states;
 329
 330         if (state >= pr->power.timer_broadcast_on_state) {
 331                 unsigned long reason;
 332
 333                 reason = broadcast ?  CLOCK_EVT_NOTIFY_BROADCAST_ENTER :
 334                         CLOCK_EVT_NOTIFY_BROADCAST_EXIT;
 335                 clockevents_notify(reason, &pr->id);
 336         }
 337 }
 338
 339 #else
 340
 341 static void acpi_timer_check_state(int state, struct acpi_processor *pr,
 342                                    struct acpi_processor_cx *cstate) { }
 343 static void acpi_propagate_timer_broadcast(struct acpi_processor *pr) { }
 344 static void acpi_state_timer_broadcast(struct acpi_processor *pr,
 345                                        struct acpi_processor_cx *cx,
 346                                        int broadcast)
 347 {
 348 }
 349
 350 #endif
 351
 352 /*
 353  * Suspend / resume control
 354  */
 355 static int acpi_idle_suspend;
 356
 357 int acpi_processor_suspend(struct acpi_device * device, pm_message_t state)
 358 {
 359         acpi_idle_suspend = 1;
 360         return 0;
 361 }
 362
 363 int acpi_processor_resume(struct acpi_device * device)
 364 {
 365         acpi_idle_suspend = 0;
 366         return 0;
 367 }
 368
 369 #if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86)
 370 static int tsc_halts_in_c(int state)
 371 {
 372         switch (boot_cpu_data.x86_vendor) {
 373         case X86_VENDOR_AMD:
 374                 /*
 375                  * AMD Fam10h TSC will tick in all
 376                  * C/P/S0/S1 states when this bit is set.
 377                  */
 378                 if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC))
 379                         return 0;
 380                 /*FALL THROUGH*/
 381         case X86_VENDOR_INTEL:
 382                 /* Several cases known where TSC halts in C2 too */
 383         default:
 384                 return state > ACPI_STATE_C1;
 385         }
 386 }
 387 #endif
 388
 389 #ifndef CONFIG_CPU_IDLE
 390 static void acpi_processor_idle(void)
 391 {
 392         struct acpi_processor *pr = NULL;
 393         struct acpi_processor_cx *cx = NULL;
 394         struct acpi_processor_cx *next_state = NULL;
 395         int sleep_ticks = 0;
 396         u32 t1, t2 = 0;
 397
 398         /*
 399          * Interrupts must be disabled during bus mastering calculations and
 400          * for C2/C3 transitions.
 401          */
 402         local_irq_disable();
 403
 404         pr = processors[smp_processor_id()];
 405         if (!pr) {
 406                 local_irq_enable();
 407                 return;
 408         }
 409
 410         /*
 411          * Check whether we truly need to go idle, or should
 412          * reschedule:
 413          */
 414         if (unlikely(need_resched())) {
 415                 local_irq_enable();
 416                 return;
 417         }
 418
 419         cx = pr->power.state;
 420         if (!cx || acpi_idle_suspend) {
 421                 if (pm_idle_save)
 422                         pm_idle_save();
 423                 else
 424                         acpi_safe_halt();
 425
 426                 if (irqs_disabled())
 427                         local_irq_enable();
 428
 429                 return;
 430         }
 431
 432         /*
 433          * Check BM Activity
 434          * -----------------
 435          * Check for bus mastering activity (if required), record, and check
 436          * for demotion.
 437          */
 438         if (pr->flags.bm_check) {
 439                 u32 bm_status = 0;
 440                 unsigned long diff = jiffies - pr->power.bm_check_timestamp;
 441
 442                 if (diff > 31)
 443                         diff = 31;
 444
 445                 pr->power.bm_activity <<= diff;
 446
 447                 acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
 448                 if (bm_status) {
 449                         pr->power.bm_activity |= 0x1;
 450                         acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
 451                 }
 452                 /*
 453                  * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
 454                  * the true state of bus mastering activity; forcing us to
 455                  * manually check the BMIDEA bit of each IDE channel.
 456                  */
 457                 else if (errata.piix4.bmisx) {
 458                         if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
 459                             || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
 460                                 pr->power.bm_activity |= 0x1;
 461                 }
 462
 463                 pr->power.bm_check_timestamp = jiffies;
 464
 465                 /*
 466                  * If bus mastering is or was active this jiffy, demote
 467                  * to avoid a faulty transition.  Note that the processor
 468                  * won't enter a low-power state during this call (to this
 469                  * function) but should upon the next.
 470                  *
 471                  * TBD: A better policy might be to fallback to the demotion
 472                  *      state (use it for this quantum only) istead of
 473                  *      demoting -- and rely on duration as our sole demotion
 474                  *      qualification.  This may, however, introduce DMA
 475                  *      issues (e.g. floppy DMA transfer overrun/underrun).
 476                  */
 477                 if ((pr->power.bm_activity & 0x1) &&
 478                     cx->demotion.threshold.bm) {
 479                         local_irq_enable();
 480                         next_state = cx->demotion.state;
 481                         goto end;
 482                 }
 483         }
 484
 485 #ifdef CONFIG_HOTPLUG_CPU
 486         /*
 487          * Check for P_LVL2_UP flag before entering C2 and above on
 488          * an SMP system. We do it here instead of doing it at _CST/P_LVL
 489          * detection phase, to work cleanly with logical CPU hotplug.
 490          */
 491         if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
 492             !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
 493                 cx = &pr->power.states[ACPI_STATE_C1];
 494 #endif
 495
 496         /*
 497          * Sleep:
 498          * ------
 499          * Invoke the current Cx state to put the processor to sleep.
 500          */
 501         if (cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) {
 502                 current_thread_info()->status &= ~TS_POLLING;
 503                 /*
 504                  * TS_POLLING-cleared state must be visible before we
 505                  * test NEED_RESCHED:
 506                  */
 507                 smp_mb();
 508                 if (need_resched()) {
 509                         current_thread_info()->status |= TS_POLLING;
 510                         local_irq_enable();
 511                         return;
 512                 }
 513         }
 514
 515         switch (cx->type) {
 516
 517         case ACPI_STATE_C1:
 518                 /*
 519                  * Invoke C1.
 520                  * Use the appropriate idle routine, the one that would
 521                  * be used without acpi C-states.
 522                  */
 523                 if (pm_idle_save)
 524                         pm_idle_save();
 525                 else
 526                         acpi_safe_halt();
 527
 528                 /*
 529                  * TBD: Can't get time duration while in C1, as resumes
 530                  *      go to an ISR rather than here.  Need to instrument
 531                  *      base interrupt handler.
 532                  *
 533                  * Note: the TSC better not stop in C1, sched_clock() will
 534                  *       skew otherwise.
 535                  */
 536                 sleep_ticks = 0xFFFFFFFF;
 537                 if (irqs_disabled())
 538                         local_irq_enable();
 539
 540                 break;
 541
 542         case ACPI_STATE_C2:
 543                 /* Get start time (ticks) */
 544                 t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
 545                 /* Tell the scheduler that we are going deep-idle: */
 546                 sched_clock_idle_sleep_event();
 547                 /* Invoke C2 */
 548                 acpi_state_timer_broadcast(pr, cx, 1);
 549                 acpi_cstate_enter(cx);
 550                 /* Get end time (ticks) */
 551                 t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
 552
 553 #if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86)
 554                 /* TSC halts in C2, so notify users */
 555                 if (tsc_halts_in_c(ACPI_STATE_C2))
 556                         mark_tsc_unstable("possible TSC halt in C2");
 557 #endif
 558                 /* Compute time (ticks) that we were actually asleep */
 559                 sleep_ticks = ticks_elapsed(t1, t2);
 560
 561                 /* Tell the scheduler how much we idled: */
 562                 sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
 563
 564                 /* Re-enable interrupts */
 565                 local_irq_enable();
 566                 /* Do not account our idle-switching overhead: */
 567                 sleep_ticks -= cx->latency_ticks + C2_OVERHEAD;
 568
 569                 current_thread_info()->status |= TS_POLLING;
 570                 acpi_state_timer_broadcast(pr, cx, 0);
 571                 break;
 572
 573         case ACPI_STATE_C3:
 574                 acpi_unlazy_tlb(smp_processor_id());
 575                 /*
 576                  * Must be done before busmaster disable as we might
 577                  * need to access HPET !
 578                  */
 579                 acpi_state_timer_broadcast(pr, cx, 1);
 580                 /*
 581                  * disable bus master
 582                  * bm_check implies we need ARB_DIS
 583                  * !bm_check implies we need cache flush
 584                  * bm_control implies whether we can do ARB_DIS
 585                  *
 586                  * That leaves a case where bm_check is set and bm_control is
 587                  * not set. In that case we cannot do much, we enter C3
 588                  * without doing anything.
 589                  */
 590                 if (pr->flags.bm_check && pr->flags.bm_control) {
 591                         if (atomic_inc_return(&c3_cpu_count) ==
 592                             num_online_cpus()) {
 593                                 /*
 594                                  * All CPUs are trying to go to C3
 595                                  * Disable bus master arbitration
 596                                  */
 597                                 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1);
 598                         }
 599                 } else if (!pr->flags.bm_check) {
 600                         /* SMP with no shared cache... Invalidate cache  */
 601                         ACPI_FLUSH_CPU_CACHE();
 602                 }
 603
 604                 /* Get start time (ticks) */
 605                 t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
 606                 /* Invoke C3 */
 607                 /* Tell the scheduler that we are going deep-idle: */
 608                 sched_clock_idle_sleep_event();
 609                 acpi_cstate_enter(cx);
 610                 /* Get end time (ticks) */
 611                 t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
 612                 if (pr->flags.bm_check && pr->flags.bm_control) {
 613                         /* Enable bus master arbitration */
 614                         atomic_dec(&c3_cpu_count);
 615                         acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0);
 616                 }
 617
 618 #if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86)
 619                 /* TSC halts in C3, so notify users */
 620                 if (tsc_halts_in_c(ACPI_STATE_C3))
 621                         mark_tsc_unstable("TSC halts in C3");
 622 #endif
 623                 /* Compute time (ticks) that we were actually asleep */
 624                 sleep_ticks = ticks_elapsed(t1, t2);
 625                 /* Tell the scheduler how much we idled: */
 626                 sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
 627
 628                 /* Re-enable interrupts */
 629                 local_irq_enable();
 630                 /* Do not account our idle-switching overhead: */
 631                 sleep_ticks -= cx->latency_ticks + C3_OVERHEAD;
 632
 633                 current_thread_info()->status |= TS_POLLING;
 634                 acpi_state_timer_broadcast(pr, cx, 0);
 635                 break;
 636
 637         default:
 638                 local_irq_enable();
 639                 return;
 640         }
 641         cx->usage++;
 642         if ((cx->type != ACPI_STATE_C1) && (sleep_ticks > 0))
 643                 cx->time += sleep_ticks;
 644
 645         next_state = pr->power.state;
 646
 647 #ifdef CONFIG_HOTPLUG_CPU
 648         /* Don't do promotion/demotion */
 649         if ((cx->type == ACPI_STATE_C1) && (num_online_cpus() > 1) &&
 650             !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED)) {
 651                 next_state = cx;
 652                 goto end;
 653         }
 654 #endif
 655
 656         /*
 657          * Promotion?
 658          * ----------
 659          * Track the number of longs (time asleep is greater than threshold)
 660          * and promote when the count threshold is reached.  Note that bus
 661          * mastering activity may prevent promotions.
 662          * Do not promote above max_cstate.
 663          */
 664         if (cx->promotion.state &&
 665             ((cx->promotion.state - pr->power.states) <= max_cstate)) {
 666                 if (sleep_ticks > cx->promotion.threshold.ticks &&
 667                   cx->promotion.state->latency <=
 668                                 pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY)) {
 669                         cx->promotion.count++;
 670                         cx->demotion.count = 0;
 671                         if (cx->promotion.count >=
 672                             cx->promotion.threshold.count) {
 673                                 if (pr->flags.bm_check) {
 674                                         if (!
 675                                             (pr->power.bm_activity & cx->
 676                                              promotion.threshold.bm)) {
 677                                                 next_state =
 678                                                     cx->promotion.state;
 679                                                 goto end;
 680                                         }
 681                                 } else {
 682                                         next_state = cx->promotion.state;
 683                                         goto end;
 684                                 }
 685                         }
 686                 }
 687         }
 688
 689         /*
 690          * Demotion?
 691          * ---------
 692          * Track the number of shorts (time asleep is less than time threshold)
 693          * and demote when the usage threshold is reached.
 694          */
 695         if (cx->demotion.state) {
 696                 if (sleep_ticks < cx->demotion.threshold.ticks) {
 697                         cx->demotion.count++;
 698                         cx->promotion.count = 0;
 699                         if (cx->demotion.count >= cx->demotion.threshold.count) {
 700                                 next_state = cx->demotion.state;
 701                                 goto end;
 702                         }
 703                 }
 704         }
 705
 706       end:
 707         /*
 708          * Demote if current state exceeds max_cstate
 709          * or if the latency of the current state is unacceptable
 710          */
 711         if ((pr->power.state - pr->power.states) > max_cstate ||
 712                 pr->power.state->latency >
 713                                 pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY)) {
 714                 if (cx->demotion.state)
 715                         next_state = cx->demotion.state;
 716         }
 717
 718         /*
 719          * New Cx State?
 720          * -------------
 721          * If we're going to start using a new Cx state we must clean up
 722          * from the previous and prepare to use the new.
 723          */
 724         if (next_state != pr->power.state)
 725                 acpi_processor_power_activate(pr, next_state);
 726 }
 727
 728 static int acpi_processor_set_power_policy(struct acpi_processor *pr)
 729 {
 730         unsigned int i;
 731         unsigned int state_is_set = 0;
 732         struct acpi_processor_cx *lower = NULL;
 733         struct acpi_processor_cx *higher = NULL;
 734         struct acpi_processor_cx *cx;
 735
 736
 737         if (!pr)
 738                 return -EINVAL;
 739
 740         /*
 741          * This function sets the default Cx state policy (OS idle handler).
 742          * Our scheme is to promote quickly to C2 but more conservatively
 743          * to C3.  We're favoring C2  for its characteristics of low latency
 744          * (quick response), good power savings, and ability to allow bus
 745          * mastering activity.  Note that the Cx state policy is completely
 746          * customizable and can be altered dynamically.
 747          */
 748
 749         /* startup state */
 750         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 751                 cx = &pr->power.states[i];
 752                 if (!cx->valid)
 753                         continue;
 754
 755                 if (!state_is_set)
 756                         pr->power.state = cx;
 757                 state_is_set++;
 758                 break;
 759         }
 760
 761         if (!state_is_set)
 762                 return -ENODEV;
 763
 764         /* demotion */
 765         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 766                 cx = &pr->power.states[i];
 767                 if (!cx->valid)
 768                         continue;
 769
 770                 if (lower) {
 771                         cx->demotion.state = lower;
 772                         cx->demotion.threshold.ticks = cx->latency_ticks;
 773                         cx->demotion.threshold.count = 1;
 774                         if (cx->type == ACPI_STATE_C3)
 775                                 cx->demotion.threshold.bm = bm_history;
 776                 }
 777
 778                 lower = cx;
 779         }
 780
 781         /* promotion */
 782         for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) {
 783                 cx = &pr->power.states[i];
 784                 if (!cx->valid)
 785                         continue;
 786
 787                 if (higher) {
 788                         cx->promotion.state = higher;
 789                         cx->promotion.threshold.ticks = cx->latency_ticks;
 790                         if (cx->type >= ACPI_STATE_C2)
 791                                 cx->promotion.threshold.count = 4;
 792                         else
 793                                 cx->promotion.threshold.count = 10;
 794                         if (higher->type == ACPI_STATE_C3)
 795                                 cx->promotion.threshold.bm = bm_history;
 796                 }
 797
 798                 higher = cx;
 799         }
 800
 801         return 0;
 802 }
 803 #endif /* !CONFIG_CPU_IDLE */
 804
 805 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
 806 {
 807
 808         if (!pr)
 809                 return -EINVAL;
 810
 811         if (!pr->pblk)
 812                 return -ENODEV;
 813
 814         /* if info is obtained from pblk/fadt, type equals state */
 815         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
 816         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 817
 818 #ifndef CONFIG_HOTPLUG_CPU
 819         /*
 820          * Check for P_LVL2_UP flag before entering C2 and above on
 821          * an SMP system.
 822          */
 823         if ((num_online_cpus() > 1) &&
 824             !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
 825                 return -ENODEV;
 826 #endif
 827
 828         /* determine C2 and C3 address from pblk */
 829         pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
 830         pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
 831
 832         /* determine latencies from FADT */
 833         pr->power.states[ACPI_STATE_C2].latency = acpi_gbl_FADT.C2latency;
 834         pr->power.states[ACPI_STATE_C3].latency = acpi_gbl_FADT.C3latency;
 835
 836         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 837                           "lvl2[0x%08x] lvl3[0x%08x]\n",
 838                           pr->power.states[ACPI_STATE_C2].address,
 839                           pr->power.states[ACPI_STATE_C3].address));
 840
 841         return 0;
 842 }
 843
 844 static int acpi_processor_get_power_info_default(struct acpi_processor *pr)
 845 {
 846         if (!pr->power.states[ACPI_STATE_C1].valid) {
 847                 /* set the first C-State to C1 */
 848                 /* all processors need to support C1 */
 849                 pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 850                 pr->power.states[ACPI_STATE_C1].valid = 1;
 851                 pr->power.states[ACPI_STATE_C1].entry_method = ACPI_CSTATE_HALT;
 852         }
 853         /* the C0 state only exists as a filler in our array */
 854         pr->power.states[ACPI_STATE_C0].valid = 1;
 855         return 0;
 856 }
 857
 858 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
 859 {
 860         acpi_status status = 0;
 861         acpi_integer count;
 862         int current_count;
 863         int i;
 864         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 865         union acpi_object *cst;
 866
 867
 868         if (nocst)
 869                 return -ENODEV;
 870
 871         current_count = 0;
 872
 873         status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer);
 874         if (ACPI_FAILURE(status)) {
 875                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n"));
 876                 return -ENODEV;
 877         }
 878
 879         cst = buffer.pointer;
 880
 881         /* There must be at least 2 elements */
 882         if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) {
 883                 printk(KERN_ERR PREFIX "not enough elements in _CST\n");
 884                 status = -EFAULT;
 885                 goto end;
 886         }
 887
 888         count = cst->package.elements[0].integer.value;
 889
 890         /* Validate number of power states. */
 891         if (count < 1 || count != cst->package.count - 1) {
 892                 printk(KERN_ERR PREFIX "count given by _CST is not valid\n");
 893                 status = -EFAULT;
 894                 goto end;
 895         }
 896
 897         /* Tell driver that at least _CST is supported. */
 898         pr->flags.has_cst = 1;
 899
 900         for (i = 1; i <= count; i++) {
 901                 union acpi_object *element;
 902                 union acpi_object *obj;
 903                 struct acpi_power_register *reg;
 904                 struct acpi_processor_cx cx;
 905
 906                 memset(&cx, 0, sizeof(cx));
 907
 908                 element = &(cst->package.elements[i]);
 909                 if (element->type != ACPI_TYPE_PACKAGE)
 910                         continue;
 911
 912                 if (element->package.count != 4)
 913                         continue;
 914
 915                 obj = &(element->package.elements[0]);
 916
 917                 if (obj->type != ACPI_TYPE_BUFFER)
 918                         continue;
 919
 920                 reg = (struct acpi_power_register *)obj->buffer.pointer;
 921
 922                 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
 923                     (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE))
 924                         continue;
 925
 926                 /* There should be an easy way to extract an integer... */
 927                 obj = &(element->package.elements[1]);
 928                 if (obj->type != ACPI_TYPE_INTEGER)
 929                         continue;
 930
 931                 cx.type = obj->integer.value;
 932                 /*
 933                  * Some buggy BIOSes won't list C1 in _CST -
 934                  * Let acpi_processor_get_power_info_default() handle them later
 935                  */
 936                 if (i == 1 && cx.type != ACPI_STATE_C1)
 937                         current_count++;
 938
 939                 cx.address = reg->address;
 940                 cx.index = current_count + 1;
 941
 942                 cx.entry_method = ACPI_CSTATE_SYSTEMIO;
 943                 if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
 944                         if (acpi_processor_ffh_cstate_probe
 945                                         (pr->id, &cx, reg) == 0) {
 946                                 cx.entry_method = ACPI_CSTATE_FFH;
 947                         } else if (cx.type == ACPI_STATE_C1) {
 948                                 /*
 949                                  * C1 is a special case where FIXED_HARDWARE
 950                                  * can be handled in non-MWAIT way as well.
 951                                  * In that case, save this _CST entry info.
 952                                  * Otherwise, ignore this info and continue.
 953                                  */
 954                                 cx.entry_method = ACPI_CSTATE_HALT;
 955                                 snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
 956                         } else {
 957                                 continue;
 958                         }
 959                 } else {
 960                         snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI IOPORT 0x%x",
 961                                  cx.address);
 962                 }
 963
 964                 if (cx.type == ACPI_STATE_C1) {
 965                         cx.valid = 1;
 966                 }
 967
 968                 obj = &(element->package.elements[2]);
 969                 if (obj->type != ACPI_TYPE_INTEGER)
 970                         continue;
 971
 972                 cx.latency = obj->integer.value;
 973
 974                 obj = &(element->package.elements[3]);
 975                 if (obj->type != ACPI_TYPE_INTEGER)
 976                         continue;
 977
 978                 cx.power = obj->integer.value;
 979
 980                 current_count++;
 981                 memcpy(&(pr->power.states[current_count]), &cx, sizeof(cx));
 982
 983                 /*
 984                  * We support total ACPI_PROCESSOR_MAX_POWER - 1
 985                  * (From 1 through ACPI_PROCESSOR_MAX_POWER - 1)
 986                  */
 987                 if (current_count >= (ACPI_PROCESSOR_MAX_POWER - 1)) {
 988                         printk(KERN_WARNING
 989                                "Limiting number of power states to max (%d)\n",
 990                                ACPI_PROCESSOR_MAX_POWER);
 991                         printk(KERN_WARNING
 992                                "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
 993                         break;
 994                 }
 995         }
 996
 997         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n",
 998                           current_count));
 999
1000         /* Validate number of power states discovered */
1001         if (current_count < 2)
1002                 status = -EFAULT;
1003
1004       end:
1005         kfree(buffer.pointer);
1006
1007         return status;
1008 }
1009
1010 static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx)
1011 {
1012
1013         if (!cx->address)
1014                 return;
1015
1016         /*
1017          * C2 latency must be less than or equal to 100
1018          * microseconds.
1019          */
1020         else if (cx->latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
1021                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1022                                   "latency too large [%d]\n", cx->latency));
1023                 return;
1024         }
1025
1026         /*
1027          * Otherwise we've met all of our C2 requirements.
1028          * Normalize the C2 latency to expidite policy
1029          */
1030         cx->valid = 1;
1031
1032 #ifndef CONFIG_CPU_IDLE
1033         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
1034 #else
1035         cx->latency_ticks = cx->latency;
1036 #endif
1037
1038         return;
1039 }
1040
1041 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
1042                                            struct acpi_processor_cx *cx)
1043 {
1044         static int bm_check_flag;
1045
1046
1047         if (!cx->address)
1048                 return;
1049
1050         /*
1051          * C3 latency must be less than or equal to 1000
1052          * microseconds.
1053          */
1054         else if (cx->latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
1055                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1056                                   "latency too large [%d]\n", cx->latency));
1057                 return;
1058         }
1059
1060         /*
1061          * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
1062          * DMA transfers are used by any ISA device to avoid livelock.
1063          * Note that we could disable Type-F DMA (as recommended by
1064          * the erratum), but this is known to disrupt certain ISA
1065          * devices thus we take the conservative approach.
1066          */
1067         else if (errata.piix4.fdma) {
1068                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1069                                   "C3 not supported on PIIX4 with Type-F DMA\n"));
1070                 return;
1071         }
1072
1073         /* All the logic here assumes flags.bm_check is same across all CPUs */
1074         if (!bm_check_flag) {
1075                 /* Determine whether bm_check is needed based on CPU  */
1076                 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
1077                 bm_check_flag = pr->flags.bm_check;
1078         } else {
1079                 pr->flags.bm_check = bm_check_flag;
1080         }
1081
1082         if (pr->flags.bm_check) {
1083                 if (!pr->flags.bm_control) {
1084                         if (pr->flags.has_cst != 1) {
1085                                 /* bus mastering control is necessary */
1086                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1087                                         "C3 support requires BM control\n"));
1088                                 return;
1089                         } else {
1090                                 /* Here we enter C3 without bus mastering */
1091                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1092                                         "C3 support without BM control\n"));
1093                         }
1094                 }
1095         } else {
1096                 /*
1097                  * WBINVD should be set in fadt, for C3 state to be
1098                  * supported on when bm_check is not required.
1099                  */
1100                 if (!(acpi_gbl_FADT.flags & ACPI_FADT_WBINVD)) {
1101                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1102                                           "Cache invalidation should work properly"
1103                                           " for C3 to be enabled on SMP systems\n"));
1104                         return;
1105                 }
1106                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
1107         }
1108
1109         /*
1110          * Otherwise we've met all of our C3 requirements.
1111          * Normalize the C3 latency to expidite policy.  Enable
1112          * checking of bus mastering status (bm_check) so we can
1113          * use this in our C3 policy
1114          */
1115         cx->valid = 1;
1116
1117 #ifndef CONFIG_CPU_IDLE
1118         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
1119 #else
1120         cx->latency_ticks = cx->latency;
1121 #endif
1122
1123         return;
1124 }
1125
1126 static int acpi_processor_power_verify(struct acpi_processor *pr)
1127 {
1128         unsigned int i;
1129         unsigned int working = 0;
1130
1131         pr->power.timer_broadcast_on_state = INT_MAX;
1132
1133         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
1134                 struct acpi_processor_cx *cx = &pr->power.states[i];
1135
1136                 switch (cx->type) {
1137                 case ACPI_STATE_C1:
1138                         cx->valid = 1;
1139                         break;
1140
1141                 case ACPI_STATE_C2:
1142                         acpi_processor_power_verify_c2(cx);
1143                         if (cx->valid)
1144                                 acpi_timer_check_state(i, pr, cx);
1145                         break;
1146
1147                 case ACPI_STATE_C3:
1148                         acpi_processor_power_verify_c3(pr, cx);
1149                         if (cx->valid)
1150                                 acpi_timer_check_state(i, pr, cx);
1151                         break;
1152                 }
1153
1154                 if (cx->valid)
1155                         working++;
1156         }
1157
1158         acpi_propagate_timer_broadcast(pr);
1159
1160         return (working);
1161 }
1162
1163 static int acpi_processor_get_power_info(struct acpi_processor *pr)
1164 {
1165         unsigned int i;
1166         int result;
1167
1168
1169         /* NOTE: the idle thread may not be running while calling
1170          * this function */
1171
1172         /* Zero initialize all the C-states info. */
1173         memset(pr->power.states, 0, sizeof(pr->power.states));
1174
1175         result = acpi_processor_get_power_info_cst(pr);
1176         if (result == -ENODEV)
1177                 result = acpi_processor_get_power_info_fadt(pr);
1178
1179         if (result)
1180                 return result;
1181
1182         acpi_processor_get_power_info_default(pr);
1183
1184         pr->power.count = acpi_processor_power_verify(pr);
1185
1186 #ifndef CONFIG_CPU_IDLE
1187         /*
1188          * Set Default Policy
1189          * ------------------
1190          * Now that we know which states are supported, set the default
1191          * policy.  Note that this policy can be changed dynamically
1192          * (e.g. encourage deeper sleeps to conserve battery life when
1193          * not on AC).
1194          */
1195         result = acpi_processor_set_power_policy(pr);
1196         if (result)
1197                 return result;
1198 #endif
1199
1200         /*
1201          * if one state of type C2 or C3 is available, mark this
1202          * CPU as being "idle manageable"
1203          */
1204         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
1205                 if (pr->power.states[i].valid) {
1206                         pr->power.count = i;
1207                         if (pr->power.states[i].type >= ACPI_STATE_C2)
1208                                 pr->flags.power = 1;
1209                 }
1210         }
1211
1212         return 0;
1213 }
1214
1215 static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset)
1216 {
1217         struct acpi_processor *pr = seq->private;
1218         unsigned int i;
1219
1220
1221         if (!pr)
1222                 goto end;
1223
1224         seq_printf(seq, "active state:            C%zd\n"
1225                    "max_cstate:              C%d\n"
1226                    "bus master activity:     %08x\n"
1227                    "maximum allowed latency: %d usec\n",
1228                    pr->power.state ? pr->power.state - pr->power.states : 0,
1229                    max_cstate, (unsigned)pr->power.bm_activity,
1230                    pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY));
1231
1232         seq_puts(seq, "states:\n");
1233
1234         for (i = 1; i <= pr->power.count; i++) {
1235                 seq_printf(seq, "   %cC%d:                  ",
1236                            (&pr->power.states[i] ==
1237                             pr->power.state ? '*' : ' '), i);
1238
1239                 if (!pr->power.states[i].valid) {
1240                         seq_puts(seq, "<not supported>\n");
1241                         continue;
1242                 }
1243
1244                 switch (pr->power.states[i].type) {
1245                 case ACPI_STATE_C1:
1246                         seq_printf(seq, "type[C1] ");
1247                         break;
1248                 case ACPI_STATE_C2:
1249                         seq_printf(seq, "type[C2] ");
1250                         break;
1251                 case ACPI_STATE_C3:
1252                         seq_printf(seq, "type[C3] ");
1253                         break;
1254                 default:
1255                         seq_printf(seq, "type[--] ");
1256                         break;
1257                 }
1258
1259                 if (pr->power.states[i].promotion.state)
1260                         seq_printf(seq, "promotion[C%zd] ",
1261                                    (pr->power.states[i].promotion.state -
1262                                     pr->power.states));
1263                 else
1264                         seq_puts(seq, "promotion[--] ");
1265
1266                 if (pr->power.states[i].demotion.state)
1267                         seq_printf(seq, "demotion[C%zd] ",
1268                                    (pr->power.states[i].demotion.state -
1269                                     pr->power.states));
1270                 else
1271                         seq_puts(seq, "demotion[--] ");
1272
1273                 seq_printf(seq, "latency[%03d] usage[%08d] duration[%020llu]\n",
1274                            pr->power.states[i].latency,
1275                            pr->power.states[i].usage,
1276                            (unsigned long long)pr->power.states[i].time);
1277         }
1278
1279       end:
1280         return 0;
1281 }
1282
1283 static int acpi_processor_power_open_fs(struct inode *inode, struct file *file)
1284 {
1285         return single_open(file, acpi_processor_power_seq_show,
1286                            PDE(inode)->data);
1287 }
1288
1289 static const struct file_operations acpi_processor_power_fops = {
1290         .open = acpi_processor_power_open_fs,
1291         .read = seq_read,
1292         .llseek = seq_lseek,
1293         .release = single_release,
1294 };
1295
1296 #ifndef CONFIG_CPU_IDLE
1297
1298 int acpi_processor_cst_has_changed(struct acpi_processor *pr)
1299 {
1300         int result = 0;
1301
1302         if (boot_option_idle_override)
1303                 return 0;
1304
1305         if (!pr)
1306                 return -EINVAL;
1307
1308         if (nocst) {
1309                 return -ENODEV;
1310         }
1311
1312         if (!pr->flags.power_setup_done)
1313                 return -ENODEV;
1314
1315         /* Fall back to the default idle loop */
1316         pm_idle = pm_idle_save;
1317         synchronize_sched();    /* Relies on interrupts forcing exit from idle. */
1318
1319         pr->flags.power = 0;
1320         result = acpi_processor_get_power_info(pr);
1321         if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
1322                 pm_idle = acpi_processor_idle;
1323
1324         return result;
1325 }
1326
1327 #ifdef CONFIG_SMP
1328 static void smp_callback(void *v)
1329 {
1330         /* we already woke the CPU up, nothing more to do */
1331 }
1332
1333 /*
1334  * This function gets called when a part of the kernel has a new latency
1335  * requirement.  This means we need to get all processors out of their C-state,
1336  * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
1337  * wakes them all right up.
1338  */
1339 static int acpi_processor_latency_notify(struct notifier_block *b,
1340                 unsigned long l, void *v)
1341 {
1342         smp_call_function(smp_callback, NULL, 0, 1);
1343         return NOTIFY_OK;
1344 }
1345
1346 static struct notifier_block acpi_processor_latency_notifier = {
1347         .notifier_call = acpi_processor_latency_notify,
1348 };
1349
1350 #endif
1351
1352 #else /* CONFIG_CPU_IDLE */
1353
1354 /**
1355  * acpi_idle_bm_check - checks if bus master activity was detected
1356  */
1357 static int acpi_idle_bm_check(void)
1358 {
1359         u32 bm_status = 0;
1360
1361         acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
1362         if (bm_status)
1363                 acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
1364         /*
1365          * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
1366          * the true state of bus mastering activity; forcing us to
1367          * manually check the BMIDEA bit of each IDE channel.
1368          */
1369         else if (errata.piix4.bmisx) {
1370                 if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
1371                     || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
1372                         bm_status = 1;
1373         }
1374         return bm_status;
1375 }
1376
1377 /**
1378  * acpi_idle_update_bm_rld - updates the BM_RLD bit depending on target state
1379  * @pr: the processor
1380  * @target: the new target state
1381  */
1382 static inline void acpi_idle_update_bm_rld(struct acpi_processor *pr,
1383                                            struct acpi_processor_cx *target)
1384 {
1385         if (pr->flags.bm_rld_set && target->type != ACPI_STATE_C3) {
1386                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
1387                 pr->flags.bm_rld_set = 0;
1388         }
1389
1390         if (!pr->flags.bm_rld_set && target->type == ACPI_STATE_C3) {
1391                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
1392                 pr->flags.bm_rld_set = 1;
1393         }
1394 }
1395
1396 /**
1397  * acpi_idle_do_entry - a helper function that does C2 and C3 type entry
1398  * @cx: cstate data
1399  *
1400  * Caller disables interrupt before call and enables interrupt after return.
1401  */
1402 static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx)
1403 {
1404         if (cx->entry_method == ACPI_CSTATE_FFH) {
1405                 /* Call into architectural FFH based C-state */
1406                 acpi_processor_ffh_cstate_enter(cx);
1407         } else if (cx->entry_method == ACPI_CSTATE_HALT) {
1408                 acpi_safe_halt();
1409         } else {
1410                 int unused;
1411                 /* IO port based C-state */
1412                 inb(cx->address);
1413                 /* Dummy wait op - must do something useless after P_LVL2 read
1414                    because chipsets cannot guarantee that STPCLK# signal
1415                    gets asserted in time to freeze execution properly. */
1416                 unused = inl(acpi_gbl_FADT.xpm_timer_block.address);
1417         }
1418 }
1419
1420 /**
1421  * acpi_idle_enter_c1 - enters an ACPI C1 state-type
1422  * @dev: the target CPU
1423  * @state: the state data
1424  *
1425  * This is equivalent to the HALT instruction.
1426  */
1427 static int acpi_idle_enter_c1(struct cpuidle_device *dev,
1428                               struct cpuidle_state *state)
1429 {
1430         u32 t1, t2;
1431         struct acpi_processor *pr;
1432         struct acpi_processor_cx *cx = cpuidle_get_statedata(state);
1433
1434         pr = processors[smp_processor_id()];
1435
1436         if (unlikely(!pr))
1437                 return 0;
1438
1439         local_irq_disable();
1440
1441         /* Do not access any ACPI IO ports in suspend path */
1442         if (acpi_idle_suspend) {
1443                 acpi_safe_halt();
1444                 local_irq_enable();
1445                 return 0;
1446         }
1447
1448         if (pr->flags.bm_check)
1449                 acpi_idle_update_bm_rld(pr, cx);
1450
1451         t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
1452         acpi_idle_do_entry(cx);
1453         t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
1454
1455         local_irq_enable();
1456         cx->usage++;
1457
1458         return ticks_elapsed_in_us(t1, t2);
1459 }
1460
1461 /**
1462  * acpi_idle_enter_simple - enters an ACPI state without BM handling
1463  * @dev: the target CPU
1464  * @state: the state data
1465  */
1466 static int acpi_idle_enter_simple(struct cpuidle_device *dev,
1467                                   struct cpuidle_state *state)
1468 {
1469         struct acpi_processor *pr;
1470         struct acpi_processor_cx *cx = cpuidle_get_statedata(state);
1471         u32 t1, t2;
1472         int sleep_ticks = 0;
1473
1474         pr = processors[smp_processor_id()];
1475
1476         if (unlikely(!pr))
1477                 return 0;
1478
1479         if (acpi_idle_suspend)
1480                 return(acpi_idle_enter_c1(dev, state));
1481
1482         local_irq_disable();
1483         current_thread_info()->status &= ~TS_POLLING;
1484         /*
1485          * TS_POLLING-cleared state must be visible before we test
1486          * NEED_RESCHED:
1487          */
1488         smp_mb();
1489
1490         if (unlikely(need_resched())) {
1491                 current_thread_info()->status |= TS_POLLING;
1492                 local_irq_enable();
1493                 return 0;
1494         }
1495
1496         /*
1497          * Must be done before busmaster disable as we might need to
1498          * access HPET !
1499          */
1500         acpi_state_timer_broadcast(pr, cx, 1);
1501
1502         if (pr->flags.bm_check)
1503                 acpi_idle_update_bm_rld(pr, cx);
1504
1505         if (cx->type == ACPI_STATE_C3)
1506                 ACPI_FLUSH_CPU_CACHE();
1507
1508         t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
1509         /* Tell the scheduler that we are going deep-idle: */
1510         sched_clock_idle_sleep_event();
1511         acpi_idle_do_entry(cx);
1512         t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
1513
1514 #if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86)
1515         /* TSC could halt in idle, so notify users */
1516         if (tsc_halts_in_c(cx->type))
1517                 mark_tsc_unstable("TSC halts in idle");;
1518 #endif
1519         sleep_ticks = ticks_elapsed(t1, t2);
1520
1521         /* Tell the scheduler how much we idled: */
1522         sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
1523
1524         local_irq_enable();
1525         current_thread_info()->status |= TS_POLLING;
1526
1527         cx->usage++;
1528
1529         acpi_state_timer_broadcast(pr, cx, 0);
1530         cx->time += sleep_ticks;
1531         return ticks_elapsed_in_us(t1, t2);
1532 }
1533
1534 static int c3_cpu_count;
1535 static DEFINE_SPINLOCK(c3_lock);
1536
1537 /**
1538  * acpi_idle_enter_bm - enters C3 with proper BM handling
1539  * @dev: the target CPU
1540  * @state: the state data
1541  *
1542  * If BM is detected, the deepest non-C3 idle state is entered instead.
1543  */
1544 static int acpi_idle_enter_bm(struct cpuidle_device *dev,
1545                               struct cpuidle_state *state)
1546 {
1547         struct acpi_processor *pr;
1548         struct acpi_processor_cx *cx = cpuidle_get_statedata(state);
1549         u32 t1, t2;
1550         int sleep_ticks = 0;
1551
1552         pr = processors[smp_processor_id()];
1553
1554         if (unlikely(!pr))
1555                 return 0;
1556
1557         if (acpi_idle_suspend)
1558                 return(acpi_idle_enter_c1(dev, state));
1559
1560         if (acpi_idle_bm_check()) {
1561                 if (dev->safe_state) {
1562                         return dev->safe_state->enter(dev, dev->safe_state);
1563                 } else {
1564                         local_irq_disable();
1565                         acpi_safe_halt();
1566                         local_irq_enable();
1567                         return 0;
1568                 }
1569         }
1570
1571         local_irq_disable();
1572         current_thread_info()->status &= ~TS_POLLING;
1573         /*
1574          * TS_POLLING-cleared state must be visible before we test
1575          * NEED_RESCHED:
1576          */
1577         smp_mb();
1578
1579         if (unlikely(need_resched())) {
1580                 current_thread_info()->status |= TS_POLLING;
1581                 local_irq_enable();
1582                 return 0;
1583         }
1584
1585         acpi_unlazy_tlb(smp_processor_id());
1586
1587         /* Tell the scheduler that we are going deep-idle: */
1588         sched_clock_idle_sleep_event();
1589         /*
1590          * Must be done before busmaster disable as we might need to
1591          * access HPET !
1592          */
1593         acpi_state_timer_broadcast(pr, cx, 1);
1594
1595         acpi_idle_update_bm_rld(pr, cx);
1596
1597         /*
1598          * disable bus master
1599          * bm_check implies we need ARB_DIS
1600          * !bm_check implies we need cache flush
1601          * bm_control implies whether we can do ARB_DIS
1602          *
1603          * That leaves a case where bm_check is set and bm_control is
1604          * not set. In that case we cannot do much, we enter C3
1605          * without doing anything.
1606          */
1607         if (pr->flags.bm_check && pr->flags.bm_control) {
1608                 spin_lock(&c3_lock);
1609                 c3_cpu_count++;
1610                 /* Disable bus master arbitration when all CPUs are in C3 */
1611                 if (c3_cpu_count == num_online_cpus())
1612                         acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1);
1613                 spin_unlock(&c3_lock);
1614         } else if (!pr->flags.bm_check) {
1615                 ACPI_FLUSH_CPU_CACHE();
1616         }
1617
1618         t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
1619         acpi_idle_do_entry(cx);
1620         t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
1621
1622         /* Re-enable bus master arbitration */
1623         if (pr->flags.bm_check && pr->flags.bm_control) {
1624                 spin_lock(&c3_lock);
1625                 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0);
1626                 c3_cpu_count--;
1627                 spin_unlock(&c3_lock);
1628         }
1629
1630 #if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86)
1631         /* TSC could halt in idle, so notify users */
1632         if (tsc_halts_in_c(ACPI_STATE_C3))
1633                 mark_tsc_unstable("TSC halts in idle");
1634 #endif
1635         sleep_ticks = ticks_elapsed(t1, t2);
1636         /* Tell the scheduler how much we idled: */
1637         sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
1638
1639         local_irq_enable();
1640         current_thread_info()->status |= TS_POLLING;
1641
1642         cx->usage++;
1643
1644         acpi_state_timer_broadcast(pr, cx, 0);
1645         cx->time += sleep_ticks;
1646         return ticks_elapsed_in_us(t1, t2);
1647 }
1648
1649 struct cpuidle_driver acpi_idle_driver = {
1650         .name =         "acpi_idle",
1651         .owner =        THIS_MODULE,
1652 };
1653
1654 /**
1655  * acpi_processor_setup_cpuidle - prepares and configures CPUIDLE
1656  * @pr: the ACPI processor
1657  */
1658 static int acpi_processor_setup_cpuidle(struct acpi_processor *pr)
1659 {
1660         int i, count = CPUIDLE_DRIVER_STATE_START;
1661         struct acpi_processor_cx *cx;
1662         struct cpuidle_state *state;
1663         struct cpuidle_device *dev = &pr->power.dev;
1664
1665         if (!pr->flags.power_setup_done)
1666                 return -EINVAL;
1667
1668         if (pr->flags.power == 0) {
1669                 return -EINVAL;
1670         }
1671
1672         for (i = 0; i < CPUIDLE_STATE_MAX; i++) {
1673                 dev->states[i].name[0] = '\0';
1674                 dev->states[i].desc[0] = '\0';
1675         }
1676
1677         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
1678                 cx = &pr->power.states[i];
1679                 state = &dev->states[count];
1680
1681                 if (!cx->valid)
1682                         continue;
1683
1684 #ifdef CONFIG_HOTPLUG_CPU
1685                 if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
1686                     !pr->flags.has_cst &&
1687                     !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
1688                         continue;
1689 #endif
1690                 cpuidle_set_statedata(state, cx);
1691
1692                 snprintf(state->name, CPUIDLE_NAME_LEN, "C%d", i);
1693                 strncpy(state->desc, cx->desc, CPUIDLE_DESC_LEN);
1694                 state->exit_latency = cx->latency;
1695                 state->target_residency = cx->latency * latency_factor;
1696                 state->power_usage = cx->power;
1697
1698                 state->flags = 0;
1699                 switch (cx->type) {
1700                         case ACPI_STATE_C1:
1701                         state->flags |= CPUIDLE_FLAG_SHALLOW;
1702                         if (cx->entry_method == ACPI_CSTATE_FFH)
1703                                 state->flags |= CPUIDLE_FLAG_TIME_VALID;
1704
1705                         state->enter = acpi_idle_enter_c1;
1706                         dev->safe_state = state;
1707                         break;
1708
1709                         case ACPI_STATE_C2:
1710                         state->flags |= CPUIDLE_FLAG_BALANCED;
1711                         state->flags |= CPUIDLE_FLAG_TIME_VALID;
1712                         state->enter = acpi_idle_enter_simple;
1713                         dev->safe_state = state;
1714                         break;
1715
1716                         case ACPI_STATE_C3:
1717                         state->flags |= CPUIDLE_FLAG_DEEP;
1718                         state->flags |= CPUIDLE_FLAG_TIME_VALID;
1719                         state->flags |= CPUIDLE_FLAG_CHECK_BM;
1720                         state->enter = pr->flags.bm_check ?
1721                                         acpi_idle_enter_bm :
1722                                         acpi_idle_enter_simple;
1723                         break;
1724                 }
1725
1726                 count++;
1727                 if (count == CPUIDLE_STATE_MAX)
1728                         break;
1729         }
1730
1731         dev->state_count = count;
1732
1733         if (!count)
1734                 return -EINVAL;
1735
1736         return 0;
1737 }
1738
1739 int acpi_processor_cst_has_changed(struct acpi_processor *pr)
1740 {
1741         int ret;
1742
1743         if (boot_option_idle_override)
1744                 return 0;
1745
1746         if (!pr)
1747                 return -EINVAL;
1748
1749         if (nocst) {
1750                 return -ENODEV;
1751         }
1752
1753         if (!pr->flags.power_setup_done)
1754                 return -ENODEV;
1755
1756         cpuidle_pause_and_lock();
1757         cpuidle_disable_device(&pr->power.dev);
1758         acpi_processor_get_power_info(pr);
1759         acpi_processor_setup_cpuidle(pr);
1760         ret = cpuidle_enable_device(&pr->power.dev);
1761         cpuidle_resume_and_unlock();
1762
1763         return ret;
1764 }
1765
1766 #endif /* CONFIG_CPU_IDLE */
1767
1768 int __cpuinit acpi_processor_power_init(struct acpi_processor *pr,
1769                               struct acpi_device *device)
1770 {
1771         acpi_status status = 0;
1772         static int first_run;
1773         struct proc_dir_entry *entry = NULL;
1774         unsigned int i;
1775
1776         if (boot_option_idle_override)
1777                 return 0;
1778
1779         if (!first_run) {
1780                 dmi_check_system(processor_power_dmi_table);
1781                 max_cstate = acpi_processor_cstate_check(max_cstate);
1782                 if (max_cstate < ACPI_C_STATES_MAX)
1783                         printk(KERN_NOTICE
1784                                "ACPI: processor limited to max C-state %d\n",
1785                                max_cstate);
1786                 first_run++;
1787 #if !defined(CONFIG_CPU_IDLE) && defined(CONFIG_SMP)
1788                 pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY,
1789                                 &acpi_processor_latency_notifier);
1790 #endif
1791         }
1792
1793         if (!pr)
1794                 return -EINVAL;
1795
1796         if (acpi_gbl_FADT.cst_control && !nocst) {
1797                 status =
1798                     acpi_os_write_port(acpi_gbl_FADT.smi_command, acpi_gbl_FADT.cst_control, 8);
1799                 if (ACPI_FAILURE(status)) {
1800                         ACPI_EXCEPTION((AE_INFO, status,
1801                                         "Notifying BIOS of _CST ability failed"));
1802                 }
1803         }
1804
1805         acpi_processor_get_power_info(pr);
1806         pr->flags.power_setup_done = 1;
1807
1808         /*
1809          * Install the idle handler if processor power management is supported.
1810          * Note that we use previously set idle handler will be used on
1811          * platforms that only support C1.
1812          */
1813         if (pr->flags.power) {
1814 #ifdef CONFIG_CPU_IDLE
1815                 acpi_processor_setup_cpuidle(pr);
1816                 pr->power.dev.cpu = pr->id;
1817                 if (cpuidle_register_device(&pr->power.dev))
1818                         return -EIO;
1819 #endif
1820
1821                 printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id);
1822                 for (i = 1; i <= pr->power.count; i++)
1823                         if (pr->power.states[i].valid)
1824                                 printk(" C%d[C%d]", i,
1825                                        pr->power.states[i].type);
1826                 printk(")\n");
1827
1828 #ifndef CONFIG_CPU_IDLE
1829                 if (pr->id == 0) {
1830                         pm_idle_save = pm_idle;
1831                         pm_idle = acpi_processor_idle;
1832                 }
1833 #endif
1834         }
1835
1836         /* 'power' [R] */
1837         entry = create_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1838                                   S_IRUGO, acpi_device_dir(device));
1839         if (!entry)
1840                 return -EIO;
1841         else {
1842                 entry->proc_fops = &acpi_processor_power_fops;
1843                 entry->data = acpi_driver_data(device);
1844                 entry->owner = THIS_MODULE;
1845         }
1846
1847         return 0;
1848 }
1849
1850 int acpi_processor_power_exit(struct acpi_processor *pr,
1851                               struct acpi_device *device)
1852 {
1853         if (boot_option_idle_override)
1854                 return 0;
1855
1856 #ifdef CONFIG_CPU_IDLE
1857         if (pr->flags.power)
1858                 cpuidle_unregister_device(&pr->power.dev);
1859 #endif
1860         pr->flags.power_setup_done = 0;
1861
1862         if (acpi_device_dir(device))
1863                 remove_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1864                                   acpi_device_dir(device));
1865
1866 #ifndef CONFIG_CPU_IDLE
1867
1868         /* Unregister the idle handler when processor #0 is removed. */
1869         if (pr->id == 0) {
1870                 pm_idle = pm_idle_save;
1871
1872                 /*
1873                  * We are about to unload the current idle thread pm callback
1874                  * (pm_idle), Wait for all processors to update cached/local
1875                  * copies of pm_idle before proceeding.
1876                  */
1877                 cpu_idle_wait();
1878 #ifdef CONFIG_SMP
1879                 pm_qos_remove_notifier(PM_QOS_CPU_DMA_LATENCY,
1880                                 &acpi_processor_latency_notifier);
1881 #endif
1882         }
1883 #endif
1884
1885         return 0;
1886 }