2 # For a description of the syntax of this configuration file,
3 # see Documentation/kbuild/kconfig-language.txt.
6 mainmenu "Linux Kernel Configuration"
12 This is Linux's home port. Linux was originally native to the Intel
13 386, and runs on all the later x86 processors including the Intel
14 486, 586, Pentiums, and various instruction-set-compatible chips by
15 AMD, Cyrix, and others.
28 config GENERIC_ISA_DMA
38 menu "Processor type and features"
41 prompt "Subarchitecture Type"
47 Choose this option if your computer is a standard PC or compatible.
52 Select this for an AMD Elan processor.
54 Do not use this option for K6/Athlon/Opteron processors!
56 If unsure, choose "PC-compatible" instead.
61 Voyager is an MCA-based 32-way capable SMP architecture proprietary
62 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
66 If you do not specifically know you have a Voyager based machine,
67 say N here, otherwise the kernel you build will not be bootable.
70 bool "NUMAQ (IBM/Sequent)"
74 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
75 multiquad box. This changes the way that processors are bootstrapped,
76 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
77 You will need a new lynxer.elf file to flash your firmware with - send
78 email to <Martin.Bligh@us.ibm.com>.
81 bool "Summit/EXA (IBM x440)"
84 This option is needed for IBM systems that use the Summit/EXA chipset.
85 In particular, it is needed for the x440.
87 If you don't have one of these computers, you should say N here.
90 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
93 This option is needed for the systems that have more than 8 CPUs
94 and if the system is not of any sub-arch type above.
96 If you don't have such a system, you should say N here.
99 bool "SGI 320/540 (Visual Workstation)"
101 The SGI Visual Workstation series is an IA32-based workstation
102 based on SGI systems chips with some legacy PC hardware attached.
104 Say Y here to create a kernel to run on the SGI 320 or 540.
106 A kernel compiled for the Visual Workstation will not run on PCs
107 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
109 config X86_GENERICARCH
110 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
113 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
114 It is intended for a generic binary kernel.
117 bool "Support for Unisys ES7000 IA32 series"
120 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
121 supposed to run on an IA32-based Unisys ES7000 system.
122 Only choose this option if you have such a system, otherwise you
130 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
132 config X86_SUMMIT_NUMA
135 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
137 config X86_CYCLONE_TIMER
140 depends on X86_SUMMIT || X86_GENERICARCH
142 config ES7000_CLUSTERED_APIC
145 depends on SMP && X86_ES7000 && MPENTIUMIII
150 prompt "Processor family"
156 This is the processor type of your CPU. This information is used for
157 optimizing purposes. In order to compile a kernel that can run on
158 all x86 CPU types (albeit not optimally fast), you can specify
161 The kernel will not necessarily run on earlier architectures than
162 the one you have chosen, e.g. a Pentium optimized kernel will run on
163 a PPro, but not necessarily on a i486.
165 Here are the settings recommended for greatest speed:
166 - "386" for the AMD/Cyrix/Intel 386DX/DXL/SL/SLC/SX, Cyrix/TI
167 486DLC/DLC2, UMC 486SX-S and NexGen Nx586. Only "386" kernels
168 will run on a 386 class machine.
169 - "486" for the AMD/Cyrix/IBM/Intel 486DX/DX2/DX4 or
170 SL/SLC/SLC2/SLC3/SX/SX2 and UMC U5D or U5S.
171 - "586" for generic Pentium CPUs lacking the TSC
172 (time stamp counter) register.
173 - "Pentium-Classic" for the Intel Pentium.
174 - "Pentium-MMX" for the Intel Pentium MMX.
175 - "Pentium-Pro" for the Intel Pentium Pro.
176 - "Pentium-II" for the Intel Pentium II or pre-Coppermine Celeron.
177 - "Pentium-III" for the Intel Pentium III or Coppermine Celeron.
178 - "Pentium-4" for the Intel Pentium 4 or P4-based Celeron.
179 - "K6" for the AMD K6, K6-II and K6-III (aka K6-3D).
180 - "Athlon" for the AMD K7 family (Athlon/Duron/Thunderbird).
181 - "Crusoe" for the Transmeta Crusoe series.
182 - "Efficeon" for the Transmeta Efficeon series.
183 - "Winchip-C6" for original IDT Winchip.
184 - "Winchip-2" for IDT Winchip 2.
185 - "Winchip-2A" for IDT Winchips with 3dNow! capabilities.
186 - "MediaGX/Geode" for Cyrix MediaGX aka Geode.
187 - "CyrixIII/VIA C3" for VIA Cyrix III or VIA C3.
188 - "VIA C3-2 for VIA C3-2 "Nehemiah" (model 9 and above).
190 If you don't know what to do, choose "386".
195 Select this for a 486 series processor, either Intel or one of the
196 compatible processors from AMD, Cyrix, IBM, or Intel. Includes DX,
197 DX2, and DX4 variants; also SL/SLC/SLC2/SLC3/SX/SX2 and UMC U5D or
201 bool "586/K5/5x86/6x86/6x86MX"
203 Select this for an 586 or 686 series processor such as the AMD K5,
204 the Cyrix 5x86, 6x86 and 6x86MX. This choice does not
205 assume the RDTSC (Read Time Stamp Counter) instruction.
208 bool "Pentium-Classic"
210 Select this for a Pentium Classic processor with the RDTSC (Read
211 Time Stamp Counter) instruction for benchmarking.
216 Select this for a Pentium with the MMX graphics/multimedia
217 extended instructions.
222 Select this for Intel Pentium Pro chips. This enables the use of
223 Pentium Pro extended instructions, and disables the init-time guard
224 against the f00f bug found in earlier Pentiums.
227 bool "Pentium-II/Celeron(pre-Coppermine)"
229 Select this for Intel chips based on the Pentium-II and
230 pre-Coppermine Celeron core. This option enables an unaligned
231 copy optimization, compiles the kernel with optimization flags
232 tailored for the chip, and applies any applicable Pentium Pro
236 bool "Pentium-III/Celeron(Coppermine)/Pentium-III Xeon"
238 Select this for Intel chips based on the Pentium-III and
239 Celeron-Coppermine core. This option enables use of some
240 extended prefetch instructions in addition to the Pentium II
246 Select this for Intel Pentium M (not Pentium-4 M)
250 bool "Pentium-4/Celeron(P4-based)/Pentium-4 M/Xeon"
252 Select this for Intel Pentium 4 chips. This includes the
253 Pentium 4, P4-based Celeron and Xeon, and Pentium-4 M
254 (not Pentium M) chips. This option enables compile flags
255 optimized for the chip, uses the correct cache shift, and
256 applies any applicable Pentium III optimizations.
259 bool "K6/K6-II/K6-III"
261 Select this for an AMD K6-family processor. Enables use of
262 some extended instructions, and passes appropriate optimization
266 bool "Athlon/Duron/K7"
268 Select this for an AMD Athlon K7-family processor. Enables use of
269 some extended instructions, and passes appropriate optimization
273 bool "Opteron/Athlon64/Hammer/K8"
275 Select this for an AMD Opteron or Athlon64 Hammer-family processor. Enables
276 use of some extended instructions, and passes appropriate optimization
282 Select this for a Transmeta Crusoe processor. Treats the processor
283 like a 586 with TSC, and sets some GCC optimization flags (like a
284 Pentium Pro with no alignment requirements).
289 Select this for a Transmeta Efficeon processor.
294 Select this for an IDT Winchip C6 chip. Linux and GCC
295 treat this chip as a 586TSC with some extended instructions
296 and alignment requirements.
301 Select this for an IDT Winchip-2. Linux and GCC
302 treat this chip as a 586TSC with some extended instructions
303 and alignment requirements.
306 bool "Winchip-2A/Winchip-3"
308 Select this for an IDT Winchip-2A or 3. Linux and GCC
309 treat this chip as a 586TSC with some extended instructions
310 and alignment reqirements. Also enable out of order memory
311 stores for this CPU, which can increase performance of some
317 Select this for a Cyrix MediaGX aka Geode chip. Linux and GCC
318 treat this chip as a 586TSC with some extended instructions
319 and alignment reqirements.
322 bool "CyrixIII/VIA-C3"
324 Select this for a Cyrix III or C3 chip. Presently Linux and GCC
325 treat this chip as a generic 586. Whilst the CPU is 686 class,
326 it lacks the cmov extension which gcc assumes is present when
328 Note that Nehemiah (Model 9) and above will not boot with this
329 kernel due to them lacking the 3DNow! instructions used in earlier
330 incarnations of the CPU.
333 bool "VIA C3-2 (Nehemiah)"
335 Select this for a VIA C3 "Nehemiah". Selecting this enables usage
336 of SSE and tells gcc to treat the CPU as a 686.
337 Note, this kernel will not boot on older (pre model 9) C3s.
342 bool "Generic x86 support"
344 Instead of just including optimizations for the selected
345 x86 variant (e.g. PII, Crusoe or Athlon), include some more
346 generic optimizations as well. This will make the kernel
347 perform better on x86 CPUs other than that selected.
349 This is really intended for distributors who need more
350 generic optimizations.
355 # Define implied options from the CPU selection here
367 config X86_L1_CACHE_SHIFT
369 default "7" if MPENTIUM4 || X86_GENERIC
370 default "4" if X86_ELAN || M486 || M386
371 default "5" if MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCRUSOE || MEFFICEON || MCYRIXIII || MK6 || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || M586 || MVIAC3_2 || MGEODE
372 default "6" if MK7 || MK8 || MPENTIUMM
374 config RWSEM_GENERIC_SPINLOCK
379 config RWSEM_XCHGADD_ALGORITHM
384 config GENERIC_CALIBRATE_DELAY
388 config X86_PPRO_FENCE
390 depends on M686 || M586MMX || M586TSC || M586 || M486 || M386 || MGEODE
395 depends on M586MMX || M586TSC || M586 || M486 || M386
398 config X86_WP_WORKS_OK
418 config X86_ALIGNMENT_16
420 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || X86_ELAN || MK6 || M586MMX || M586TSC || M586 || M486 || MVIAC3_2 || MGEODE
425 depends on MK7 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || MK8 || MEFFICEON
428 config X86_INTEL_USERCOPY
430 depends on MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M586MMX || X86_GENERIC || MK8 || MK7 || MEFFICEON
433 config X86_USE_PPRO_CHECKSUM
435 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC3_2 || MEFFICEON
440 depends on MCYRIXIII || MK7
445 depends on (MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MGEODE) && MTRR
449 bool "HPET Timer Support"
451 This enables the use of the HPET for the kernel's internal timer.
452 HPET is the next generation timer replacing legacy 8254s.
453 You can safely choose Y here. However, HPET will only be
454 activated if the platform and the BIOS support this feature.
455 Otherwise the 8254 will be used for timing services.
457 Choose N to continue using the legacy 8254 timer.
459 config HPET_EMULATE_RTC
460 bool "Provide RTC interrupt"
461 depends on HPET_TIMER && RTC=y
464 bool "Symmetric multi-processing support"
466 This enables support for systems with more than one CPU. If you have
467 a system with only one CPU, like most personal computers, say N. If
468 you have a system with more than one CPU, say Y.
470 If you say N here, the kernel will run on single and multiprocessor
471 machines, but will use only one CPU of a multiprocessor machine. If
472 you say Y here, the kernel will run on many, but not all,
473 singleprocessor machines. On a singleprocessor machine, the kernel
474 will run faster if you say N here.
476 Note that if you say Y here and choose architecture "586" or
477 "Pentium" under "Processor family", the kernel will not work on 486
478 architectures. Similarly, multiprocessor kernels for the "PPro"
479 architecture may not work on all Pentium based boards.
481 People using multiprocessor machines who say Y here should also say
482 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
483 Management" code will be disabled if you say Y here.
485 See also the <file:Documentation/smp.txt>,
486 <file:Documentation/i386/IO-APIC.txt>,
487 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
488 <http://www.tldp.org/docs.html#howto>.
490 If you don't know what to do here, say N.
493 int "Maximum number of CPUs (2-255)"
496 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
499 This allows you to specify the maximum number of CPUs which this
500 kernel will support. The maximum supported value is 255 and the
501 minimum value which makes sense is 2.
503 This is purely to save memory - each supported CPU adds
504 approximately eight kilobytes to the kernel image.
507 bool "SMT (Hyperthreading) scheduler support"
511 SMT scheduler support improves the CPU scheduler's decision making
512 when dealing with Intel Pentium 4 chips with HyperThreading at a
513 cost of slightly increased overhead in some places. If unsure say
517 bool "Preemptible Kernel"
519 This option reduces the latency of the kernel when reacting to
520 real-time or interactive events by allowing a low priority process to
521 be preempted even if it is in kernel mode executing a system call.
522 This allows applications to run more reliably even when the system is
525 Say Y here if you are building a kernel for a desktop, embedded
526 or real-time system. Say N if you are unsure.
529 bool "Preempt The Big Kernel Lock"
533 This option reduces the latency of the kernel by making the
534 big kernel lock preemptible.
536 Say Y here if you are building a kernel for a desktop system.
537 Say N if you are unsure.
540 bool "Local APIC support on uniprocessors"
541 depends on !SMP && !(X86_VISWS || X86_VOYAGER)
543 A local APIC (Advanced Programmable Interrupt Controller) is an
544 integrated interrupt controller in the CPU. If you have a single-CPU
545 system which has a processor with a local APIC, you can say Y here to
546 enable and use it. If you say Y here even though your machine doesn't
547 have a local APIC, then the kernel will still run with no slowdown at
548 all. The local APIC supports CPU-generated self-interrupts (timer,
549 performance counters), and the NMI watchdog which detects hard
553 bool "IO-APIC support on uniprocessors"
554 depends on X86_UP_APIC
556 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
557 SMP-capable replacement for PC-style interrupt controllers. Most
558 SMP systems and many recent uniprocessor systems have one.
560 If you have a single-CPU system with an IO-APIC, you can say Y here
561 to use it. If you say Y here even though your machine doesn't have
562 an IO-APIC, then the kernel will still run with no slowdown at all.
564 config X86_LOCAL_APIC
566 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER)
571 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER))
574 config X86_VISWS_APIC
581 depends on (MWINCHIP3D || MWINCHIP2 || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2 || MGEODE) && !X86_NUMAQ
585 bool "Machine Check Exception"
586 depends on !X86_VOYAGER
588 Machine Check Exception support allows the processor to notify the
589 kernel if it detects a problem (e.g. overheating, component failure).
590 The action the kernel takes depends on the severity of the problem,
591 ranging from a warning message on the console, to halting the machine.
592 Your processor must be a Pentium or newer to support this - check the
593 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
594 have a design flaw which leads to false MCE events - hence MCE is
595 disabled on all P5 processors, unless explicitly enabled with "mce"
596 as a boot argument. Similarly, if MCE is built in and creates a
597 problem on some new non-standard machine, you can boot with "nomce"
598 to disable it. MCE support simply ignores non-MCE processors like
599 the 386 and 486, so nearly everyone can say Y here.
601 config X86_MCE_NONFATAL
602 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
605 Enabling this feature starts a timer that triggers every 5 seconds which
606 will look at the machine check registers to see if anything happened.
607 Non-fatal problems automatically get corrected (but still logged).
608 Disable this if you don't want to see these messages.
609 Seeing the messages this option prints out may be indicative of dying hardware,
610 or out-of-spec (ie, overclocked) hardware.
611 This option only does something on certain CPUs.
612 (AMD Athlon/Duron and Intel Pentium 4)
614 config X86_MCE_P4THERMAL
615 bool "check for P4 thermal throttling interrupt."
616 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
618 Enabling this feature will cause a message to be printed when the P4
619 enters thermal throttling.
622 tristate "Toshiba Laptop support"
624 This adds a driver to safely access the System Management Mode of
625 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
626 not work on models with a Phoenix BIOS. The System Management Mode
627 is used to set the BIOS and power saving options on Toshiba portables.
629 For information on utilities to make use of this driver see the
630 Toshiba Linux utilities web site at:
631 <http://www.buzzard.org.uk/toshiba/>.
633 Say Y if you intend to run this kernel on a Toshiba portable.
637 tristate "Dell laptop support"
639 This adds a driver to safely access the System Management Mode
640 of the CPU on the Dell Inspiron 8000. The System Management Mode
641 is used to read cpu temperature and cooling fan status and to
642 control the fans on the I8K portables.
644 This driver has been tested only on the Inspiron 8000 but it may
645 also work with other Dell laptops. You can force loading on other
646 models by passing the parameter `force=1' to the module. Use at
649 For information on utilities to make use of this driver see the
650 I8K Linux utilities web site at:
651 <http://people.debian.org/~dz/i8k/>
653 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
656 config X86_REBOOTFIXUPS
657 bool "Enable X86 board specific fixups for reboot"
661 This enables chipset and/or board specific fixups to be done
662 in order to get reboot to work correctly. This is only needed on
663 some combinations of hardware and BIOS. The symptom, for which
664 this config is intended, is when reboot ends with a stalled/hung
667 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
670 Say Y if you want to enable the fixup. Currently, it's safe to
671 enable this option even if you don't need it.
675 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
677 If you say Y here and also to "/dev file system support" in the
678 'File systems' section, you will be able to update the microcode on
679 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
680 Pentium III, Pentium 4, Xeon etc. You will obviously need the
681 actual microcode binary data itself which is not shipped with the
684 For latest news and information on obtaining all the required
685 ingredients for this driver, check:
686 <http://www.urbanmyth.org/microcode/>.
688 To compile this driver as a module, choose M here: the
689 module will be called microcode.
692 tristate "/dev/cpu/*/msr - Model-specific register support"
694 This device gives privileged processes access to the x86
695 Model-Specific Registers (MSRs). It is a character device with
696 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
697 MSR accesses are directed to a specific CPU on multi-processor
701 tristate "/dev/cpu/*/cpuid - CPU information support"
703 This device gives processes access to the x86 CPUID instruction to
704 be executed on a specific processor. It is a character device
705 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
708 source "drivers/firmware/Kconfig"
711 prompt "High Memory Support"
717 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
718 However, the address space of 32-bit x86 processors is only 4
719 Gigabytes large. That means that, if you have a large amount of
720 physical memory, not all of it can be "permanently mapped" by the
721 kernel. The physical memory that's not permanently mapped is called
724 If you are compiling a kernel which will never run on a machine with
725 more than 1 Gigabyte total physical RAM, answer "off" here (default
726 choice and suitable for most users). This will result in a "3GB/1GB"
727 split: 3GB are mapped so that each process sees a 3GB virtual memory
728 space and the remaining part of the 4GB virtual memory space is used
729 by the kernel to permanently map as much physical memory as
732 If the machine has between 1 and 4 Gigabytes physical RAM, then
735 If more than 4 Gigabytes is used then answer "64GB" here. This
736 selection turns Intel PAE (Physical Address Extension) mode on.
737 PAE implements 3-level paging on IA32 processors. PAE is fully
738 supported by Linux, PAE mode is implemented on all recent Intel
739 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
740 then the kernel will not boot on CPUs that don't support PAE!
742 The actual amount of total physical memory will either be
743 auto detected or can be forced by using a kernel command line option
744 such as "mem=256M". (Try "man bootparam" or see the documentation of
745 your boot loader (lilo or loadlin) about how to pass options to the
746 kernel at boot time.)
748 If unsure, say "off".
753 Select this if you have a 32-bit processor and between 1 and 4
754 gigabytes of physical RAM.
759 Select this if you have a 32-bit processor and more than 4
760 gigabytes of physical RAM.
766 depends on HIGHMEM64G || HIGHMEM4G
771 depends on HIGHMEM64G
774 # Common NUMA Features
776 bool "Numa Memory Allocation and Scheduler Support"
777 depends on SMP && HIGHMEM64G && (X86_NUMAQ || X86_GENERICARCH || (X86_SUMMIT && ACPI))
779 default y if (X86_NUMAQ || X86_SUMMIT)
781 # Need comments to help the hapless user trying to turn on NUMA support
782 comment "NUMA (NUMA-Q) requires SMP, 64GB highmem support"
783 depends on X86_NUMAQ && (!HIGHMEM64G || !SMP)
785 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
786 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
793 config HAVE_ARCH_BOOTMEM_NODE
798 config HAVE_MEMORY_PRESENT
800 depends on DISCONTIGMEM
803 config NEED_NODE_MEMMAP_SIZE
805 depends on DISCONTIGMEM
809 bool "Allocate 3rd-level pagetables from highmem"
810 depends on HIGHMEM4G || HIGHMEM64G
812 The VM uses one page table entry for each page of physical memory.
813 For systems with a lot of RAM, this can be wasteful of precious
814 low memory. Setting this option will put user-space page table
815 entries in high memory.
817 config MATH_EMULATION
818 bool "Math emulation"
820 Linux can emulate a math coprocessor (used for floating point
821 operations) if you don't have one. 486DX and Pentium processors have
822 a math coprocessor built in, 486SX and 386 do not, unless you added
823 a 487DX or 387, respectively. (The messages during boot time can
824 give you some hints here ["man dmesg"].) Everyone needs either a
825 coprocessor or this emulation.
827 If you don't have a math coprocessor, you need to say Y here; if you
828 say Y here even though you have a coprocessor, the coprocessor will
829 be used nevertheless. (This behavior can be changed with the kernel
830 command line option "no387", which comes handy if your coprocessor
831 is broken. Try "man bootparam" or see the documentation of your boot
832 loader (lilo or loadlin) about how to pass options to the kernel at
833 boot time.) This means that it is a good idea to say Y here if you
834 intend to use this kernel on different machines.
836 More information about the internals of the Linux math coprocessor
837 emulation can be found in <file:arch/i386/math-emu/README>.
839 If you are not sure, say Y; apart from resulting in a 66 KB bigger
840 kernel, it won't hurt.
843 bool "MTRR (Memory Type Range Register) support"
845 On Intel P6 family processors (Pentium Pro, Pentium II and later)
846 the Memory Type Range Registers (MTRRs) may be used to control
847 processor access to memory ranges. This is most useful if you have
848 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
849 allows bus write transfers to be combined into a larger transfer
850 before bursting over the PCI/AGP bus. This can increase performance
851 of image write operations 2.5 times or more. Saying Y here creates a
852 /proc/mtrr file which may be used to manipulate your processor's
853 MTRRs. Typically the X server should use this.
855 This code has a reasonably generic interface so that similar
856 control registers on other processors can be easily supported
859 The Cyrix 6x86, 6x86MX and M II processors have Address Range
860 Registers (ARRs) which provide a similar functionality to MTRRs. For
861 these, the ARRs are used to emulate the MTRRs.
862 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
863 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
864 write-combining. All of these processors are supported by this code
865 and it makes sense to say Y here if you have one of them.
867 Saying Y here also fixes a problem with buggy SMP BIOSes which only
868 set the MTRRs for the boot CPU and not for the secondary CPUs. This
869 can lead to all sorts of problems, so it's good to say Y here.
871 You can safely say Y even if your machine doesn't have MTRRs, you'll
872 just add about 9 KB to your kernel.
874 See <file:Documentation/mtrr.txt> for more information.
877 bool "Boot from EFI support (EXPERIMENTAL)"
881 This enables the the kernel to boot on EFI platforms using
882 system configuration information passed to it from the firmware.
883 This also enables the kernel to use any EFI runtime services that are
884 available (such as the EFI variable services).
886 This option is only useful on systems that have EFI firmware
887 and will result in a kernel image that is ~8k larger. In addition,
888 you must use the latest ELILO loader available at
889 <http://elilo.sourceforge.net> in order to take advantage of
890 kernel initialization using EFI information (neither GRUB nor LILO know
891 anything about EFI). However, even with this option, the resultant
892 kernel should continue to boot on existing non-EFI platforms.
895 bool "Enable kernel irq balancing"
896 depends on SMP && X86_IO_APIC
899 The default yes will allow the kernel to do irq load balancing.
900 Saying no will keep the kernel from doing irq load balancing.
904 depends on (SMP || PREEMPT) && X86_CMPXCHG
907 # turning this on wastes a bunch of space.
908 # Summit needs it only when NUMA is on
911 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
915 bool "Use register arguments (EXPERIMENTAL)"
916 depends on EXPERIMENTAL
919 Compile the kernel with -mregparm=3. This uses a different ABI
920 and passes the first three arguments of a function call in registers.
921 This will probably break binary only modules.
923 This feature is only enabled for gcc-3.0 and later - earlier compilers
924 generate incorrect output with certain kernel constructs when
928 bool "Enable seccomp to safely compute untrusted bytecode"
932 This kernel feature is useful for number crunching applications
933 that may need to compute untrusted bytecode during their
934 execution. By using pipes or other transports made available to
935 the process as file descriptors supporting the read/write
936 syscalls, it's possible to isolate those applications in
937 their own address space using seccomp. Once seccomp is
938 enabled via /proc/<pid>/seccomp, it cannot be disabled
939 and the task is only allowed to execute a few safe syscalls
940 defined by each seccomp mode.
942 If unsure, say Y. Only embedded should say N here.
947 menu "Power management options (ACPI, APM)"
948 depends on !X86_VOYAGER
950 source kernel/power/Kconfig
952 source "drivers/acpi/Kconfig"
954 menu "APM (Advanced Power Management) BIOS Support"
955 depends on PM && !X86_VISWS
958 tristate "APM (Advanced Power Management) BIOS support"
961 APM is a BIOS specification for saving power using several different
962 techniques. This is mostly useful for battery powered laptops with
963 APM compliant BIOSes. If you say Y here, the system time will be
964 reset after a RESUME operation, the /proc/apm device will provide
965 battery status information, and user-space programs will receive
966 notification of APM "events" (e.g. battery status change).
968 If you select "Y" here, you can disable actual use of the APM
969 BIOS by passing the "apm=off" option to the kernel at boot time.
971 Note that the APM support is almost completely disabled for
972 machines with more than one CPU.
974 In order to use APM, you will need supporting software. For location
975 and more information, read <file:Documentation/pm.txt> and the
976 Battery Powered Linux mini-HOWTO, available from
977 <http://www.tldp.org/docs.html#howto>.
979 This driver does not spin down disk drives (see the hdparm(8)
980 manpage ("man 8 hdparm") for that), and it doesn't turn off
981 VESA-compliant "green" monitors.
983 This driver does not support the TI 4000M TravelMate and the ACER
984 486/DX4/75 because they don't have compliant BIOSes. Many "green"
985 desktop machines also don't have compliant BIOSes, and this driver
986 may cause those machines to panic during the boot phase.
988 Generally, if you don't have a battery in your machine, there isn't
989 much point in using this driver and you should say N. If you get
990 random kernel OOPSes or reboots that don't seem to be related to
991 anything, try disabling/enabling this option (or disabling/enabling
994 Some other things you should try when experiencing seemingly random,
997 1) make sure that you have enough swap space and that it is
999 2) pass the "no-hlt" option to the kernel
1000 3) switch on floating point emulation in the kernel and pass
1001 the "no387" option to the kernel
1002 4) pass the "floppy=nodma" option to the kernel
1003 5) pass the "mem=4M" option to the kernel (thereby disabling
1004 all but the first 4 MB of RAM)
1005 6) make sure that the CPU is not over clocked.
1006 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1007 8) disable the cache from your BIOS settings
1008 9) install a fan for the video card or exchange video RAM
1009 10) install a better fan for the CPU
1010 11) exchange RAM chips
1011 12) exchange the motherboard.
1013 To compile this driver as a module, choose M here: the
1014 module will be called apm.
1016 config APM_IGNORE_USER_SUSPEND
1017 bool "Ignore USER SUSPEND"
1020 This option will ignore USER SUSPEND requests. On machines with a
1021 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1022 series notebooks, it is necessary to say Y because of a BIOS bug.
1024 config APM_DO_ENABLE
1025 bool "Enable PM at boot time"
1028 Enable APM features at boot time. From page 36 of the APM BIOS
1029 specification: "When disabled, the APM BIOS does not automatically
1030 power manage devices, enter the Standby State, enter the Suspend
1031 State, or take power saving steps in response to CPU Idle calls."
1032 This driver will make CPU Idle calls when Linux is idle (unless this
1033 feature is turned off -- see "Do CPU IDLE calls", below). This
1034 should always save battery power, but more complicated APM features
1035 will be dependent on your BIOS implementation. You may need to turn
1036 this option off if your computer hangs at boot time when using APM
1037 support, or if it beeps continuously instead of suspending. Turn
1038 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1039 T400CDT. This is off by default since most machines do fine without
1043 bool "Make CPU Idle calls when idle"
1046 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1047 On some machines, this can activate improved power savings, such as
1048 a slowed CPU clock rate, when the machine is idle. These idle calls
1049 are made after the idle loop has run for some length of time (e.g.,
1050 333 mS). On some machines, this will cause a hang at boot time or
1051 whenever the CPU becomes idle. (On machines with more than one CPU,
1052 this option does nothing.)
1054 config APM_DISPLAY_BLANK
1055 bool "Enable console blanking using APM"
1058 Enable console blanking using the APM. Some laptops can use this to
1059 turn off the LCD backlight when the screen blanker of the Linux
1060 virtual console blanks the screen. Note that this is only used by
1061 the virtual console screen blanker, and won't turn off the backlight
1062 when using the X Window system. This also doesn't have anything to
1063 do with your VESA-compliant power-saving monitor. Further, this
1064 option doesn't work for all laptops -- it might not turn off your
1065 backlight at all, or it might print a lot of errors to the console,
1066 especially if you are using gpm.
1068 config APM_RTC_IS_GMT
1069 bool "RTC stores time in GMT"
1072 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
1073 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
1076 It is in fact recommended to store GMT in your RTC, because then you
1077 don't have to worry about daylight savings time changes. The only
1078 reason not to use GMT in your RTC is if you also run a broken OS
1079 that doesn't understand GMT.
1081 config APM_ALLOW_INTS
1082 bool "Allow interrupts during APM BIOS calls"
1085 Normally we disable external interrupts while we are making calls to
1086 the APM BIOS as a measure to lessen the effects of a badly behaving
1087 BIOS implementation. The BIOS should reenable interrupts if it
1088 needs to. Unfortunately, some BIOSes do not -- especially those in
1089 many of the newer IBM Thinkpads. If you experience hangs when you
1090 suspend, try setting this to Y. Otherwise, say N.
1092 config APM_REAL_MODE_POWER_OFF
1093 bool "Use real mode APM BIOS call to power off"
1096 Use real mode APM BIOS calls to switch off the computer. This is
1097 a work-around for a number of buggy BIOSes. Switch this option on if
1098 your computer crashes instead of powering off properly.
1102 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1106 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1109 bool "PCI support" if !X86_VISWS
1110 depends on !X86_VOYAGER
1111 default y if X86_VISWS
1113 Find out whether you have a PCI motherboard. PCI is the name of a
1114 bus system, i.e. the way the CPU talks to the other stuff inside
1115 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1116 VESA. If you have PCI, say Y, otherwise N.
1118 The PCI-HOWTO, available from
1119 <http://www.tldp.org/docs.html#howto>, contains valuable
1120 information about which PCI hardware does work under Linux and which
1124 prompt "PCI access mode"
1125 depends on PCI && !X86_VISWS
1128 On PCI systems, the BIOS can be used to detect the PCI devices and
1129 determine their configuration. However, some old PCI motherboards
1130 have BIOS bugs and may crash if this is done. Also, some embedded
1131 PCI-based systems don't have any BIOS at all. Linux can also try to
1132 detect the PCI hardware directly without using the BIOS.
1134 With this option, you can specify how Linux should detect the
1135 PCI devices. If you choose "BIOS", the BIOS will be used,
1136 if you choose "Direct", the BIOS won't be used, and if you
1137 choose "MMConfig", then PCI Express MMCONFIG will be used.
1138 If you choose "Any", the kernel will try MMCONFIG, then the
1139 direct access method and falls back to the BIOS if that doesn't
1140 work. If unsure, go with the default, which is "Any".
1145 config PCI_GOMMCONFIG
1158 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1163 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1168 depends on PCI && (PCI_GOMMCONFIG || (PCI_GOANY && ACPI))
1172 source "drivers/pci/pcie/Kconfig"
1174 source "drivers/pci/Kconfig"
1182 depends on !(X86_VOYAGER || X86_VISWS)
1184 Find out whether you have ISA slots on your motherboard. ISA is the
1185 name of a bus system, i.e. the way the CPU talks to the other stuff
1186 inside your box. Other bus systems are PCI, EISA, MicroChannel
1187 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1188 newer boards don't support it. If you have ISA, say Y, otherwise N.
1194 The Extended Industry Standard Architecture (EISA) bus was
1195 developed as an open alternative to the IBM MicroChannel bus.
1197 The EISA bus provided some of the features of the IBM MicroChannel
1198 bus while maintaining backward compatibility with cards made for
1199 the older ISA bus. The EISA bus saw limited use between 1988 and
1200 1995 when it was made obsolete by the PCI bus.
1202 Say Y here if you are building a kernel for an EISA-based machine.
1206 source "drivers/eisa/Kconfig"
1209 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1210 default y if X86_VOYAGER
1212 MicroChannel Architecture is found in some IBM PS/2 machines and
1213 laptops. It is a bus system similar to PCI or ISA. See
1214 <file:Documentation/mca.txt> (and especially the web page given
1215 there) before attempting to build an MCA bus kernel.
1217 source "drivers/mca/Kconfig"
1220 tristate "NatSemi SCx200 support"
1221 depends on !X86_VOYAGER
1223 This provides basic support for the National Semiconductor SCx200
1224 processor. Right now this is just a driver for the GPIO pins.
1226 If you don't know what to do here, say N.
1228 This support is also available as a module. If compiled as a
1229 module, it will be called scx200.
1231 source "drivers/pcmcia/Kconfig"
1233 source "drivers/pci/hotplug/Kconfig"
1237 menu "Executable file formats"
1239 source "fs/Kconfig.binfmt"
1243 source "drivers/Kconfig"
1247 source "arch/i386/oprofile/Kconfig"
1249 source "arch/i386/Kconfig.debug"
1251 source "security/Kconfig"
1253 source "crypto/Kconfig"
1255 source "lib/Kconfig"
1258 # Use the generic interrupt handling code in kernel/irq/:
1260 config GENERIC_HARDIRQS
1264 config GENERIC_IRQ_PROBE
1270 depends on SMP && !X86_VOYAGER
1275 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1278 config X86_BIOS_REBOOT
1280 depends on !(X86_VISWS || X86_VOYAGER)
1283 config X86_TRAMPOLINE
1285 depends on X86_SMP || (X86_VOYAGER && SMP)
1290 depends on X86 && !EMBEDDED