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.
21 config LOCKDEP_SUPPORT
25 config STACKTRACE_SUPPORT
29 config SEMAPHORE_SLEEPERS
44 config GENERIC_ISA_DMA
52 config GENERIC_HWEIGHT
56 config ARCH_MAY_HAVE_PC_FDC
66 menu "Processor type and features"
69 bool "Symmetric multi-processing support"
71 This enables support for systems with more than one CPU. If you have
72 a system with only one CPU, like most personal computers, say N. If
73 you have a system with more than one CPU, say Y.
75 If you say N here, the kernel will run on single and multiprocessor
76 machines, but will use only one CPU of a multiprocessor machine. If
77 you say Y here, the kernel will run on many, but not all,
78 singleprocessor machines. On a singleprocessor machine, the kernel
79 will run faster if you say N here.
81 Note that if you say Y here and choose architecture "586" or
82 "Pentium" under "Processor family", the kernel will not work on 486
83 architectures. Similarly, multiprocessor kernels for the "PPro"
84 architecture may not work on all Pentium based boards.
86 People using multiprocessor machines who say Y here should also say
87 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
88 Management" code will be disabled if you say Y here.
90 See also the <file:Documentation/smp.txt>,
91 <file:Documentation/i386/IO-APIC.txt>,
92 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
93 <http://www.tldp.org/docs.html#howto>.
95 If you don't know what to do here, say N.
98 prompt "Subarchitecture Type"
104 Choose this option if your computer is a standard PC or compatible.
109 Select this for an AMD Elan processor.
111 Do not use this option for K6/Athlon/Opteron processors!
113 If unsure, choose "PC-compatible" instead.
118 Voyager is an MCA-based 32-way capable SMP architecture proprietary
119 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
123 If you do not specifically know you have a Voyager based machine,
124 say N here, otherwise the kernel you build will not be bootable.
127 bool "NUMAQ (IBM/Sequent)"
131 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
132 multiquad box. This changes the way that processors are bootstrapped,
133 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
134 You will need a new lynxer.elf file to flash your firmware with - send
135 email to <Martin.Bligh@us.ibm.com>.
138 bool "Summit/EXA (IBM x440)"
141 This option is needed for IBM systems that use the Summit/EXA chipset.
142 In particular, it is needed for the x440.
144 If you don't have one of these computers, you should say N here.
145 If you want to build a NUMA kernel, you must select ACPI.
148 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
151 This option is needed for the systems that have more than 8 CPUs
152 and if the system is not of any sub-arch type above.
154 If you don't have such a system, you should say N here.
157 bool "SGI 320/540 (Visual Workstation)"
159 The SGI Visual Workstation series is an IA32-based workstation
160 based on SGI systems chips with some legacy PC hardware attached.
162 Say Y here to create a kernel to run on the SGI 320 or 540.
164 A kernel compiled for the Visual Workstation will not run on PCs
165 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
167 config X86_GENERICARCH
168 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
170 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
171 It is intended for a generic binary kernel.
172 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA.
175 bool "Support for Unisys ES7000 IA32 series"
178 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
179 supposed to run on an IA32-based Unisys ES7000 system.
180 Only choose this option if you have such a system, otherwise you
186 bool "Paravirtualization support (EXPERIMENTAL)"
187 depends on EXPERIMENTAL
189 Paravirtualization is a way of running multiple instances of
190 Linux on the same machine, under a hypervisor. This option
191 changes the kernel so it can modify itself when it is run
192 under a hypervisor, improving performance significantly.
193 However, when run without a hypervisor the kernel is
194 theoretically slower. If in doubt, say N.
199 depends on ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
202 config HAVE_ARCH_PARSE_SRAT
207 config X86_SUMMIT_NUMA
210 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
212 config X86_CYCLONE_TIMER
215 depends on X86_SUMMIT || X86_GENERICARCH
217 config ES7000_CLUSTERED_APIC
220 depends on SMP && X86_ES7000 && MPENTIUMIII
222 source "arch/i386/Kconfig.cpu"
225 bool "HPET Timer Support"
227 This enables the use of the HPET for the kernel's internal timer.
228 HPET is the next generation timer replacing legacy 8254s.
229 You can safely choose Y here. However, HPET will only be
230 activated if the platform and the BIOS support this feature.
231 Otherwise the 8254 will be used for timing services.
233 Choose N to continue using the legacy 8254 timer.
235 config HPET_EMULATE_RTC
237 depends on HPET_TIMER && RTC=y
241 int "Maximum number of CPUs (2-255)"
244 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
247 This allows you to specify the maximum number of CPUs which this
248 kernel will support. The maximum supported value is 255 and the
249 minimum value which makes sense is 2.
251 This is purely to save memory - each supported CPU adds
252 approximately eight kilobytes to the kernel image.
255 bool "SMT (Hyperthreading) scheduler support"
258 SMT scheduler support improves the CPU scheduler's decision making
259 when dealing with Intel Pentium 4 chips with HyperThreading at a
260 cost of slightly increased overhead in some places. If unsure say
264 bool "Multi-core scheduler support"
268 Multi-core scheduler support improves the CPU scheduler's decision
269 making when dealing with multi-core CPU chips at a cost of slightly
270 increased overhead in some places. If unsure say N here.
272 source "kernel/Kconfig.preempt"
275 bool "Local APIC support on uniprocessors"
276 depends on !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH)
278 A local APIC (Advanced Programmable Interrupt Controller) is an
279 integrated interrupt controller in the CPU. If you have a single-CPU
280 system which has a processor with a local APIC, you can say Y here to
281 enable and use it. If you say Y here even though your machine doesn't
282 have a local APIC, then the kernel will still run with no slowdown at
283 all. The local APIC supports CPU-generated self-interrupts (timer,
284 performance counters), and the NMI watchdog which detects hard
288 bool "IO-APIC support on uniprocessors"
289 depends on X86_UP_APIC
291 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
292 SMP-capable replacement for PC-style interrupt controllers. Most
293 SMP systems and many recent uniprocessor systems have one.
295 If you have a single-CPU system with an IO-APIC, you can say Y here
296 to use it. If you say Y here even though your machine doesn't have
297 an IO-APIC, then the kernel will still run with no slowdown at all.
299 config X86_LOCAL_APIC
301 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH
306 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH
309 config X86_VISWS_APIC
315 bool "Machine Check Exception"
316 depends on !X86_VOYAGER
318 Machine Check Exception support allows the processor to notify the
319 kernel if it detects a problem (e.g. overheating, component failure).
320 The action the kernel takes depends on the severity of the problem,
321 ranging from a warning message on the console, to halting the machine.
322 Your processor must be a Pentium or newer to support this - check the
323 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
324 have a design flaw which leads to false MCE events - hence MCE is
325 disabled on all P5 processors, unless explicitly enabled with "mce"
326 as a boot argument. Similarly, if MCE is built in and creates a
327 problem on some new non-standard machine, you can boot with "nomce"
328 to disable it. MCE support simply ignores non-MCE processors like
329 the 386 and 486, so nearly everyone can say Y here.
331 config X86_MCE_NONFATAL
332 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
335 Enabling this feature starts a timer that triggers every 5 seconds which
336 will look at the machine check registers to see if anything happened.
337 Non-fatal problems automatically get corrected (but still logged).
338 Disable this if you don't want to see these messages.
339 Seeing the messages this option prints out may be indicative of dying hardware,
340 or out-of-spec (ie, overclocked) hardware.
341 This option only does something on certain CPUs.
342 (AMD Athlon/Duron and Intel Pentium 4)
344 config X86_MCE_P4THERMAL
345 bool "check for P4 thermal throttling interrupt."
346 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
348 Enabling this feature will cause a message to be printed when the P4
349 enters thermal throttling.
353 bool "Enable VM86 support" if EMBEDDED
355 This option is required by programs like DOSEMU to run 16-bit legacy
356 code on X86 processors. It also may be needed by software like
357 XFree86 to initialize some video cards via BIOS. Disabling this
358 option saves about 6k.
361 tristate "Toshiba Laptop support"
363 This adds a driver to safely access the System Management Mode of
364 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
365 not work on models with a Phoenix BIOS. The System Management Mode
366 is used to set the BIOS and power saving options on Toshiba portables.
368 For information on utilities to make use of this driver see the
369 Toshiba Linux utilities web site at:
370 <http://www.buzzard.org.uk/toshiba/>.
372 Say Y if you intend to run this kernel on a Toshiba portable.
376 tristate "Dell laptop support"
378 This adds a driver to safely access the System Management Mode
379 of the CPU on the Dell Inspiron 8000. The System Management Mode
380 is used to read cpu temperature and cooling fan status and to
381 control the fans on the I8K portables.
383 This driver has been tested only on the Inspiron 8000 but it may
384 also work with other Dell laptops. You can force loading on other
385 models by passing the parameter `force=1' to the module. Use at
388 For information on utilities to make use of this driver see the
389 I8K Linux utilities web site at:
390 <http://people.debian.org/~dz/i8k/>
392 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
395 config X86_REBOOTFIXUPS
396 bool "Enable X86 board specific fixups for reboot"
400 This enables chipset and/or board specific fixups to be done
401 in order to get reboot to work correctly. This is only needed on
402 some combinations of hardware and BIOS. The symptom, for which
403 this config is intended, is when reboot ends with a stalled/hung
406 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
409 Say Y if you want to enable the fixup. Currently, it's safe to
410 enable this option even if you don't need it.
414 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
417 If you say Y here and also to "/dev file system support" in the
418 'File systems' section, you will be able to update the microcode on
419 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
420 Pentium III, Pentium 4, Xeon etc. You will obviously need the
421 actual microcode binary data itself which is not shipped with the
424 For latest news and information on obtaining all the required
425 ingredients for this driver, check:
426 <http://www.urbanmyth.org/microcode/>.
428 To compile this driver as a module, choose M here: the
429 module will be called microcode.
431 config MICROCODE_OLD_INTERFACE
437 tristate "/dev/cpu/*/msr - Model-specific register support"
439 This device gives privileged processes access to the x86
440 Model-Specific Registers (MSRs). It is a character device with
441 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
442 MSR accesses are directed to a specific CPU on multi-processor
446 tristate "/dev/cpu/*/cpuid - CPU information support"
448 This device gives processes access to the x86 CPUID instruction to
449 be executed on a specific processor. It is a character device
450 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
453 source "drivers/firmware/Kconfig"
456 prompt "High Memory Support"
461 depends on !X86_NUMAQ
463 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
464 However, the address space of 32-bit x86 processors is only 4
465 Gigabytes large. That means that, if you have a large amount of
466 physical memory, not all of it can be "permanently mapped" by the
467 kernel. The physical memory that's not permanently mapped is called
470 If you are compiling a kernel which will never run on a machine with
471 more than 1 Gigabyte total physical RAM, answer "off" here (default
472 choice and suitable for most users). This will result in a "3GB/1GB"
473 split: 3GB are mapped so that each process sees a 3GB virtual memory
474 space and the remaining part of the 4GB virtual memory space is used
475 by the kernel to permanently map as much physical memory as
478 If the machine has between 1 and 4 Gigabytes physical RAM, then
481 If more than 4 Gigabytes is used then answer "64GB" here. This
482 selection turns Intel PAE (Physical Address Extension) mode on.
483 PAE implements 3-level paging on IA32 processors. PAE is fully
484 supported by Linux, PAE mode is implemented on all recent Intel
485 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
486 then the kernel will not boot on CPUs that don't support PAE!
488 The actual amount of total physical memory will either be
489 auto detected or can be forced by using a kernel command line option
490 such as "mem=256M". (Try "man bootparam" or see the documentation of
491 your boot loader (lilo or loadlin) about how to pass options to the
492 kernel at boot time.)
494 If unsure, say "off".
498 depends on !X86_NUMAQ
500 Select this if you have a 32-bit processor and between 1 and 4
501 gigabytes of physical RAM.
505 depends on X86_CMPXCHG64
507 Select this if you have a 32-bit processor and more than 4
508 gigabytes of physical RAM.
513 depends on EXPERIMENTAL
514 prompt "Memory split" if EMBEDDED
517 Select the desired split between kernel and user memory.
519 If the address range available to the kernel is less than the
520 physical memory installed, the remaining memory will be available
521 as "high memory". Accessing high memory is a little more costly
522 than low memory, as it needs to be mapped into the kernel first.
523 Note that increasing the kernel address space limits the range
524 available to user programs, making the address space there
525 tighter. Selecting anything other than the default 3G/1G split
526 will also likely make your kernel incompatible with binary-only
529 If you are not absolutely sure what you are doing, leave this
533 bool "3G/1G user/kernel split"
534 config VMSPLIT_3G_OPT
536 bool "3G/1G user/kernel split (for full 1G low memory)"
538 bool "2G/2G user/kernel split"
540 bool "1G/3G user/kernel split"
545 default 0xB0000000 if VMSPLIT_3G_OPT
546 default 0x78000000 if VMSPLIT_2G
547 default 0x40000000 if VMSPLIT_1G
552 depends on HIGHMEM64G || HIGHMEM4G
557 depends on HIGHMEM64G
559 select RESOURCES_64BIT
561 # Common NUMA Features
563 bool "Numa Memory Allocation and Scheduler Support"
564 depends on SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI)
566 default y if (X86_NUMAQ || X86_SUMMIT)
568 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
569 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
573 default "4" if X86_NUMAQ
575 depends on NEED_MULTIPLE_NODES
577 config HAVE_ARCH_BOOTMEM_NODE
582 config ARCH_HAVE_MEMORY_PRESENT
584 depends on DISCONTIGMEM
587 config NEED_NODE_MEMMAP_SIZE
589 depends on DISCONTIGMEM || SPARSEMEM
592 config HAVE_ARCH_ALLOC_REMAP
597 config ARCH_FLATMEM_ENABLE
599 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
601 config ARCH_DISCONTIGMEM_ENABLE
605 config ARCH_DISCONTIGMEM_DEFAULT
609 config ARCH_SPARSEMEM_ENABLE
611 depends on (NUMA || (X86_PC && EXPERIMENTAL))
612 select SPARSEMEM_STATIC
614 config ARCH_SELECT_MEMORY_MODEL
616 depends on ARCH_SPARSEMEM_ENABLE
618 config ARCH_POPULATES_NODE_MAP
624 bool "Allocate 3rd-level pagetables from highmem"
625 depends on HIGHMEM4G || HIGHMEM64G
627 The VM uses one page table entry for each page of physical memory.
628 For systems with a lot of RAM, this can be wasteful of precious
629 low memory. Setting this option will put user-space page table
630 entries in high memory.
632 config MATH_EMULATION
633 bool "Math emulation"
635 Linux can emulate a math coprocessor (used for floating point
636 operations) if you don't have one. 486DX and Pentium processors have
637 a math coprocessor built in, 486SX and 386 do not, unless you added
638 a 487DX or 387, respectively. (The messages during boot time can
639 give you some hints here ["man dmesg"].) Everyone needs either a
640 coprocessor or this emulation.
642 If you don't have a math coprocessor, you need to say Y here; if you
643 say Y here even though you have a coprocessor, the coprocessor will
644 be used nevertheless. (This behavior can be changed with the kernel
645 command line option "no387", which comes handy if your coprocessor
646 is broken. Try "man bootparam" or see the documentation of your boot
647 loader (lilo or loadlin) about how to pass options to the kernel at
648 boot time.) This means that it is a good idea to say Y here if you
649 intend to use this kernel on different machines.
651 More information about the internals of the Linux math coprocessor
652 emulation can be found in <file:arch/i386/math-emu/README>.
654 If you are not sure, say Y; apart from resulting in a 66 KB bigger
655 kernel, it won't hurt.
658 bool "MTRR (Memory Type Range Register) support"
660 On Intel P6 family processors (Pentium Pro, Pentium II and later)
661 the Memory Type Range Registers (MTRRs) may be used to control
662 processor access to memory ranges. This is most useful if you have
663 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
664 allows bus write transfers to be combined into a larger transfer
665 before bursting over the PCI/AGP bus. This can increase performance
666 of image write operations 2.5 times or more. Saying Y here creates a
667 /proc/mtrr file which may be used to manipulate your processor's
668 MTRRs. Typically the X server should use this.
670 This code has a reasonably generic interface so that similar
671 control registers on other processors can be easily supported
674 The Cyrix 6x86, 6x86MX and M II processors have Address Range
675 Registers (ARRs) which provide a similar functionality to MTRRs. For
676 these, the ARRs are used to emulate the MTRRs.
677 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
678 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
679 write-combining. All of these processors are supported by this code
680 and it makes sense to say Y here if you have one of them.
682 Saying Y here also fixes a problem with buggy SMP BIOSes which only
683 set the MTRRs for the boot CPU and not for the secondary CPUs. This
684 can lead to all sorts of problems, so it's good to say Y here.
686 You can safely say Y even if your machine doesn't have MTRRs, you'll
687 just add about 9 KB to your kernel.
689 See <file:Documentation/mtrr.txt> for more information.
692 bool "Boot from EFI support"
696 This enables the kernel to boot on EFI platforms using
697 system configuration information passed to it from the firmware.
698 This also enables the kernel to use any EFI runtime services that are
699 available (such as the EFI variable services).
701 This option is only useful on systems that have EFI firmware
702 and will result in a kernel image that is ~8k larger. In addition,
703 you must use the latest ELILO loader available at
704 <http://elilo.sourceforge.net> in order to take advantage of
705 kernel initialization using EFI information (neither GRUB nor LILO know
706 anything about EFI). However, even with this option, the resultant
707 kernel should continue to boot on existing non-EFI platforms.
710 bool "Enable kernel irq balancing"
711 depends on SMP && X86_IO_APIC
714 The default yes will allow the kernel to do irq load balancing.
715 Saying no will keep the kernel from doing irq load balancing.
717 # turning this on wastes a bunch of space.
718 # Summit needs it only when NUMA is on
721 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
725 bool "Enable seccomp to safely compute untrusted bytecode"
729 This kernel feature is useful for number crunching applications
730 that may need to compute untrusted bytecode during their
731 execution. By using pipes or other transports made available to
732 the process as file descriptors supporting the read/write
733 syscalls, it's possible to isolate those applications in
734 their own address space using seccomp. Once seccomp is
735 enabled via /proc/<pid>/seccomp, it cannot be disabled
736 and the task is only allowed to execute a few safe syscalls
737 defined by each seccomp mode.
739 If unsure, say Y. Only embedded should say N here.
741 source kernel/Kconfig.hz
744 bool "kexec system call"
746 kexec is a system call that implements the ability to shutdown your
747 current kernel, and to start another kernel. It is like a reboot
748 but it is independent of the system firmware. And like a reboot
749 you can start any kernel with it, not just Linux.
751 The name comes from the similarity to the exec system call.
753 It is an ongoing process to be certain the hardware in a machine
754 is properly shutdown, so do not be surprised if this code does not
755 initially work for you. It may help to enable device hotplugging
756 support. As of this writing the exact hardware interface is
757 strongly in flux, so no good recommendation can be made.
760 bool "kernel crash dumps (EXPERIMENTAL)"
761 depends on EXPERIMENTAL
764 Generate crash dump after being started by kexec.
765 This should be normally only set in special crash dump kernels
766 which are loaded in the main kernel with kexec-tools into
767 a specially reserved region and then later executed after
768 a crash by kdump/kexec. The crash dump kernel must be compiled
769 to a memory address not used by the main kernel or BIOS using
771 For more details see Documentation/kdump/kdump.txt
774 bool "Build a relocatable kernel(EXPERIMENTAL)"
775 depends on EXPERIMENTAL
777 This build a kernel image that retains relocation information
778 so it can be loaded someplace besides the default 1MB.
779 The relocations tend to the kernel binary about 10% larger,
780 but are discarded at runtime.
782 One use is for the kexec on panic case where the recovery kernel
783 must live at a different physical address than the primary
786 config PHYSICAL_ALIGN
787 hex "Alignment value to which kernel should be aligned"
789 range 0x2000 0x400000
791 This value puts the alignment restrictions on physical address
792 where kernel is loaded and run from. Kernel is compiled for an
793 address which meets above alignment restriction.
795 If bootloader loads the kernel at a non-aligned address and
796 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
797 address aligned to above value and run from there.
799 If bootloader loads the kernel at a non-aligned address and
800 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
801 load address and decompress itself to the address it has been
802 compiled for and run from there. The address for which kernel is
803 compiled already meets above alignment restrictions. Hence the
804 end result is that kernel runs from a physical address meeting
805 above alignment restrictions.
807 Don't change this unless you know what you are doing.
810 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
811 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
813 Say Y here to experiment with turning CPUs off and on, and to
814 enable suspend on SMP systems. CPUs can be controlled through
815 /sys/devices/system/cpu.
818 bool "Compat VDSO support"
822 Map the VDSO to the predictable old-style address too.
824 Say N here if you are running a sufficiently recent glibc
825 version (2.3.3 or later), to remove the high-mapped
826 VDSO mapping and to exclusively use the randomized VDSO.
832 config ARCH_ENABLE_MEMORY_HOTPLUG
836 menu "Power management options (ACPI, APM)"
837 depends on !X86_VOYAGER
839 source kernel/power/Kconfig
841 source "drivers/acpi/Kconfig"
843 menu "APM (Advanced Power Management) BIOS Support"
844 depends on PM && !X86_VISWS
847 tristate "APM (Advanced Power Management) BIOS support"
850 APM is a BIOS specification for saving power using several different
851 techniques. This is mostly useful for battery powered laptops with
852 APM compliant BIOSes. If you say Y here, the system time will be
853 reset after a RESUME operation, the /proc/apm device will provide
854 battery status information, and user-space programs will receive
855 notification of APM "events" (e.g. battery status change).
857 If you select "Y" here, you can disable actual use of the APM
858 BIOS by passing the "apm=off" option to the kernel at boot time.
860 Note that the APM support is almost completely disabled for
861 machines with more than one CPU.
863 In order to use APM, you will need supporting software. For location
864 and more information, read <file:Documentation/pm.txt> and the
865 Battery Powered Linux mini-HOWTO, available from
866 <http://www.tldp.org/docs.html#howto>.
868 This driver does not spin down disk drives (see the hdparm(8)
869 manpage ("man 8 hdparm") for that), and it doesn't turn off
870 VESA-compliant "green" monitors.
872 This driver does not support the TI 4000M TravelMate and the ACER
873 486/DX4/75 because they don't have compliant BIOSes. Many "green"
874 desktop machines also don't have compliant BIOSes, and this driver
875 may cause those machines to panic during the boot phase.
877 Generally, if you don't have a battery in your machine, there isn't
878 much point in using this driver and you should say N. If you get
879 random kernel OOPSes or reboots that don't seem to be related to
880 anything, try disabling/enabling this option (or disabling/enabling
883 Some other things you should try when experiencing seemingly random,
886 1) make sure that you have enough swap space and that it is
888 2) pass the "no-hlt" option to the kernel
889 3) switch on floating point emulation in the kernel and pass
890 the "no387" option to the kernel
891 4) pass the "floppy=nodma" option to the kernel
892 5) pass the "mem=4M" option to the kernel (thereby disabling
893 all but the first 4 MB of RAM)
894 6) make sure that the CPU is not over clocked.
895 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
896 8) disable the cache from your BIOS settings
897 9) install a fan for the video card or exchange video RAM
898 10) install a better fan for the CPU
899 11) exchange RAM chips
900 12) exchange the motherboard.
902 To compile this driver as a module, choose M here: the
903 module will be called apm.
905 config APM_IGNORE_USER_SUSPEND
906 bool "Ignore USER SUSPEND"
909 This option will ignore USER SUSPEND requests. On machines with a
910 compliant APM BIOS, you want to say N. However, on the NEC Versa M
911 series notebooks, it is necessary to say Y because of a BIOS bug.
914 bool "Enable PM at boot time"
917 Enable APM features at boot time. From page 36 of the APM BIOS
918 specification: "When disabled, the APM BIOS does not automatically
919 power manage devices, enter the Standby State, enter the Suspend
920 State, or take power saving steps in response to CPU Idle calls."
921 This driver will make CPU Idle calls when Linux is idle (unless this
922 feature is turned off -- see "Do CPU IDLE calls", below). This
923 should always save battery power, but more complicated APM features
924 will be dependent on your BIOS implementation. You may need to turn
925 this option off if your computer hangs at boot time when using APM
926 support, or if it beeps continuously instead of suspending. Turn
927 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
928 T400CDT. This is off by default since most machines do fine without
932 bool "Make CPU Idle calls when idle"
935 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
936 On some machines, this can activate improved power savings, such as
937 a slowed CPU clock rate, when the machine is idle. These idle calls
938 are made after the idle loop has run for some length of time (e.g.,
939 333 mS). On some machines, this will cause a hang at boot time or
940 whenever the CPU becomes idle. (On machines with more than one CPU,
941 this option does nothing.)
943 config APM_DISPLAY_BLANK
944 bool "Enable console blanking using APM"
947 Enable console blanking using the APM. Some laptops can use this to
948 turn off the LCD backlight when the screen blanker of the Linux
949 virtual console blanks the screen. Note that this is only used by
950 the virtual console screen blanker, and won't turn off the backlight
951 when using the X Window system. This also doesn't have anything to
952 do with your VESA-compliant power-saving monitor. Further, this
953 option doesn't work for all laptops -- it might not turn off your
954 backlight at all, or it might print a lot of errors to the console,
955 especially if you are using gpm.
957 config APM_RTC_IS_GMT
958 bool "RTC stores time in GMT"
961 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
962 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
965 It is in fact recommended to store GMT in your RTC, because then you
966 don't have to worry about daylight savings time changes. The only
967 reason not to use GMT in your RTC is if you also run a broken OS
968 that doesn't understand GMT.
970 config APM_ALLOW_INTS
971 bool "Allow interrupts during APM BIOS calls"
974 Normally we disable external interrupts while we are making calls to
975 the APM BIOS as a measure to lessen the effects of a badly behaving
976 BIOS implementation. The BIOS should reenable interrupts if it
977 needs to. Unfortunately, some BIOSes do not -- especially those in
978 many of the newer IBM Thinkpads. If you experience hangs when you
979 suspend, try setting this to Y. Otherwise, say N.
981 config APM_REAL_MODE_POWER_OFF
982 bool "Use real mode APM BIOS call to power off"
985 Use real mode APM BIOS calls to switch off the computer. This is
986 a work-around for a number of buggy BIOSes. Switch this option on if
987 your computer crashes instead of powering off properly.
991 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
995 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
998 bool "PCI support" if !X86_VISWS
999 depends on !X86_VOYAGER
1000 default y if X86_VISWS
1002 Find out whether you have a PCI motherboard. PCI is the name of a
1003 bus system, i.e. the way the CPU talks to the other stuff inside
1004 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1005 VESA. If you have PCI, say Y, otherwise N.
1007 The PCI-HOWTO, available from
1008 <http://www.tldp.org/docs.html#howto>, contains valuable
1009 information about which PCI hardware does work under Linux and which
1013 prompt "PCI access mode"
1014 depends on PCI && !X86_VISWS
1017 On PCI systems, the BIOS can be used to detect the PCI devices and
1018 determine their configuration. However, some old PCI motherboards
1019 have BIOS bugs and may crash if this is done. Also, some embedded
1020 PCI-based systems don't have any BIOS at all. Linux can also try to
1021 detect the PCI hardware directly without using the BIOS.
1023 With this option, you can specify how Linux should detect the
1024 PCI devices. If you choose "BIOS", the BIOS will be used,
1025 if you choose "Direct", the BIOS won't be used, and if you
1026 choose "MMConfig", then PCI Express MMCONFIG will be used.
1027 If you choose "Any", the kernel will try MMCONFIG, then the
1028 direct access method and falls back to the BIOS if that doesn't
1029 work. If unsure, go with the default, which is "Any".
1034 config PCI_GOMMCONFIG
1047 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1052 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1057 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1060 source "drivers/pci/pcie/Kconfig"
1062 source "drivers/pci/Kconfig"
1070 depends on !(X86_VOYAGER || X86_VISWS)
1072 Find out whether you have ISA slots on your motherboard. ISA is the
1073 name of a bus system, i.e. the way the CPU talks to the other stuff
1074 inside your box. Other bus systems are PCI, EISA, MicroChannel
1075 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1076 newer boards don't support it. If you have ISA, say Y, otherwise N.
1082 The Extended Industry Standard Architecture (EISA) bus was
1083 developed as an open alternative to the IBM MicroChannel bus.
1085 The EISA bus provided some of the features of the IBM MicroChannel
1086 bus while maintaining backward compatibility with cards made for
1087 the older ISA bus. The EISA bus saw limited use between 1988 and
1088 1995 when it was made obsolete by the PCI bus.
1090 Say Y here if you are building a kernel for an EISA-based machine.
1094 source "drivers/eisa/Kconfig"
1097 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1098 default y if X86_VOYAGER
1100 MicroChannel Architecture is found in some IBM PS/2 machines and
1101 laptops. It is a bus system similar to PCI or ISA. See
1102 <file:Documentation/mca.txt> (and especially the web page given
1103 there) before attempting to build an MCA bus kernel.
1105 source "drivers/mca/Kconfig"
1108 tristate "NatSemi SCx200 support"
1109 depends on !X86_VOYAGER
1111 This provides basic support for National Semiconductor's
1112 (now AMD's) Geode processors. The driver probes for the
1113 PCI-IDs of several on-chip devices, so its a good dependency
1114 for other scx200_* drivers.
1116 If compiled as a module, the driver is named scx200.
1118 config SCx200HR_TIMER
1119 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1120 depends on SCx200 && GENERIC_TIME
1123 This driver provides a clocksource built upon the on-chip
1124 27MHz high-resolution timer. Its also a workaround for
1125 NSC Geode SC-1100's buggy TSC, which loses time when the
1126 processor goes idle (as is done by the scheduler). The
1127 other workaround is idle=poll boot option.
1131 depends on AGP_AMD64
1133 source "drivers/pcmcia/Kconfig"
1135 source "drivers/pci/hotplug/Kconfig"
1139 menu "Executable file formats"
1141 source "fs/Kconfig.binfmt"
1145 source "net/Kconfig"
1147 source "drivers/Kconfig"
1151 menu "Instrumentation Support"
1152 depends on EXPERIMENTAL
1154 source "arch/i386/oprofile/Kconfig"
1157 bool "Kprobes (EXPERIMENTAL)"
1158 depends on KALLSYMS && EXPERIMENTAL && MODULES
1160 Kprobes allows you to trap at almost any kernel address and
1161 execute a callback function. register_kprobe() establishes
1162 a probepoint and specifies the callback. Kprobes is useful
1163 for kernel debugging, non-intrusive instrumentation and testing.
1164 If in doubt, say "N".
1167 source "arch/i386/Kconfig.debug"
1169 source "security/Kconfig"
1171 source "crypto/Kconfig"
1173 source "lib/Kconfig"
1176 # Use the generic interrupt handling code in kernel/irq/:
1178 config GENERIC_HARDIRQS
1182 config GENERIC_IRQ_PROBE
1186 config GENERIC_PENDING_IRQ
1188 depends on GENERIC_HARDIRQS && SMP
1193 depends on SMP && !X86_VOYAGER
1198 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1201 config X86_BIOS_REBOOT
1203 depends on !(X86_VISWS || X86_VOYAGER)
1206 config X86_TRAMPOLINE
1208 depends on X86_SMP || (X86_VOYAGER && SMP)
projects / linux-2.6 / blob