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
188 depends on ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
191 config HAVE_ARCH_PARSE_SRAT
196 config X86_SUMMIT_NUMA
199 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
201 config X86_CYCLONE_TIMER
204 depends on X86_SUMMIT || X86_GENERICARCH
206 config ES7000_CLUSTERED_APIC
209 depends on SMP && X86_ES7000 && MPENTIUMIII
211 source "arch/i386/Kconfig.cpu"
214 bool "HPET Timer Support"
216 This enables the use of the HPET for the kernel's internal timer.
217 HPET is the next generation timer replacing legacy 8254s.
218 You can safely choose Y here. However, HPET will only be
219 activated if the platform and the BIOS support this feature.
220 Otherwise the 8254 will be used for timing services.
222 Choose N to continue using the legacy 8254 timer.
224 config HPET_EMULATE_RTC
226 depends on HPET_TIMER && RTC=y
230 int "Maximum number of CPUs (2-255)"
233 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
236 This allows you to specify the maximum number of CPUs which this
237 kernel will support. The maximum supported value is 255 and the
238 minimum value which makes sense is 2.
240 This is purely to save memory - each supported CPU adds
241 approximately eight kilobytes to the kernel image.
244 bool "SMT (Hyperthreading) scheduler support"
247 SMT scheduler support improves the CPU scheduler's decision making
248 when dealing with Intel Pentium 4 chips with HyperThreading at a
249 cost of slightly increased overhead in some places. If unsure say
253 bool "Multi-core scheduler support"
257 Multi-core scheduler support improves the CPU scheduler's decision
258 making when dealing with multi-core CPU chips at a cost of slightly
259 increased overhead in some places. If unsure say N here.
261 source "kernel/Kconfig.preempt"
264 bool "Local APIC support on uniprocessors"
265 depends on !SMP && !(X86_VISWS || X86_VOYAGER || X86_GENERICARCH)
267 A local APIC (Advanced Programmable Interrupt Controller) is an
268 integrated interrupt controller in the CPU. If you have a single-CPU
269 system which has a processor with a local APIC, you can say Y here to
270 enable and use it. If you say Y here even though your machine doesn't
271 have a local APIC, then the kernel will still run with no slowdown at
272 all. The local APIC supports CPU-generated self-interrupts (timer,
273 performance counters), and the NMI watchdog which detects hard
277 bool "IO-APIC support on uniprocessors"
278 depends on X86_UP_APIC
280 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
281 SMP-capable replacement for PC-style interrupt controllers. Most
282 SMP systems and many recent uniprocessor systems have one.
284 If you have a single-CPU system with an IO-APIC, you can say Y here
285 to use it. If you say Y here even though your machine doesn't have
286 an IO-APIC, then the kernel will still run with no slowdown at all.
288 config X86_LOCAL_APIC
290 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER) || X86_GENERICARCH
295 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER)) || X86_GENERICARCH
298 config X86_VISWS_APIC
304 bool "Machine Check Exception"
305 depends on !X86_VOYAGER
307 Machine Check Exception support allows the processor to notify the
308 kernel if it detects a problem (e.g. overheating, component failure).
309 The action the kernel takes depends on the severity of the problem,
310 ranging from a warning message on the console, to halting the machine.
311 Your processor must be a Pentium or newer to support this - check the
312 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
313 have a design flaw which leads to false MCE events - hence MCE is
314 disabled on all P5 processors, unless explicitly enabled with "mce"
315 as a boot argument. Similarly, if MCE is built in and creates a
316 problem on some new non-standard machine, you can boot with "nomce"
317 to disable it. MCE support simply ignores non-MCE processors like
318 the 386 and 486, so nearly everyone can say Y here.
320 config X86_MCE_NONFATAL
321 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
324 Enabling this feature starts a timer that triggers every 5 seconds which
325 will look at the machine check registers to see if anything happened.
326 Non-fatal problems automatically get corrected (but still logged).
327 Disable this if you don't want to see these messages.
328 Seeing the messages this option prints out may be indicative of dying hardware,
329 or out-of-spec (ie, overclocked) hardware.
330 This option only does something on certain CPUs.
331 (AMD Athlon/Duron and Intel Pentium 4)
333 config X86_MCE_P4THERMAL
334 bool "check for P4 thermal throttling interrupt."
335 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
337 Enabling this feature will cause a message to be printed when the P4
338 enters thermal throttling.
342 bool "Enable VM86 support" if EMBEDDED
344 This option is required by programs like DOSEMU to run 16-bit legacy
345 code on X86 processors. It also may be needed by software like
346 XFree86 to initialize some video cards via BIOS. Disabling this
347 option saves about 6k.
350 tristate "Toshiba Laptop support"
352 This adds a driver to safely access the System Management Mode of
353 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
354 not work on models with a Phoenix BIOS. The System Management Mode
355 is used to set the BIOS and power saving options on Toshiba portables.
357 For information on utilities to make use of this driver see the
358 Toshiba Linux utilities web site at:
359 <http://www.buzzard.org.uk/toshiba/>.
361 Say Y if you intend to run this kernel on a Toshiba portable.
365 tristate "Dell laptop support"
367 This adds a driver to safely access the System Management Mode
368 of the CPU on the Dell Inspiron 8000. The System Management Mode
369 is used to read cpu temperature and cooling fan status and to
370 control the fans on the I8K portables.
372 This driver has been tested only on the Inspiron 8000 but it may
373 also work with other Dell laptops. You can force loading on other
374 models by passing the parameter `force=1' to the module. Use at
377 For information on utilities to make use of this driver see the
378 I8K Linux utilities web site at:
379 <http://people.debian.org/~dz/i8k/>
381 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
384 config X86_REBOOTFIXUPS
385 bool "Enable X86 board specific fixups for reboot"
389 This enables chipset and/or board specific fixups to be done
390 in order to get reboot to work correctly. This is only needed on
391 some combinations of hardware and BIOS. The symptom, for which
392 this config is intended, is when reboot ends with a stalled/hung
395 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
398 Say Y if you want to enable the fixup. Currently, it's safe to
399 enable this option even if you don't need it.
403 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
405 If you say Y here and also to "/dev file system support" in the
406 'File systems' section, you will be able to update the microcode on
407 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
408 Pentium III, Pentium 4, Xeon etc. You will obviously need the
409 actual microcode binary data itself which is not shipped with the
412 For latest news and information on obtaining all the required
413 ingredients for this driver, check:
414 <http://www.urbanmyth.org/microcode/>.
416 To compile this driver as a module, choose M here: the
417 module will be called microcode.
420 tristate "/dev/cpu/*/msr - Model-specific register support"
422 This device gives privileged processes access to the x86
423 Model-Specific Registers (MSRs). It is a character device with
424 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
425 MSR accesses are directed to a specific CPU on multi-processor
429 tristate "/dev/cpu/*/cpuid - CPU information support"
431 This device gives processes access to the x86 CPUID instruction to
432 be executed on a specific processor. It is a character device
433 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
436 source "drivers/firmware/Kconfig"
439 prompt "High Memory Support"
444 depends on !X86_NUMAQ
446 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
447 However, the address space of 32-bit x86 processors is only 4
448 Gigabytes large. That means that, if you have a large amount of
449 physical memory, not all of it can be "permanently mapped" by the
450 kernel. The physical memory that's not permanently mapped is called
453 If you are compiling a kernel which will never run on a machine with
454 more than 1 Gigabyte total physical RAM, answer "off" here (default
455 choice and suitable for most users). This will result in a "3GB/1GB"
456 split: 3GB are mapped so that each process sees a 3GB virtual memory
457 space and the remaining part of the 4GB virtual memory space is used
458 by the kernel to permanently map as much physical memory as
461 If the machine has between 1 and 4 Gigabytes physical RAM, then
464 If more than 4 Gigabytes is used then answer "64GB" here. This
465 selection turns Intel PAE (Physical Address Extension) mode on.
466 PAE implements 3-level paging on IA32 processors. PAE is fully
467 supported by Linux, PAE mode is implemented on all recent Intel
468 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
469 then the kernel will not boot on CPUs that don't support PAE!
471 The actual amount of total physical memory will either be
472 auto detected or can be forced by using a kernel command line option
473 such as "mem=256M". (Try "man bootparam" or see the documentation of
474 your boot loader (lilo or loadlin) about how to pass options to the
475 kernel at boot time.)
477 If unsure, say "off".
481 depends on !X86_NUMAQ
483 Select this if you have a 32-bit processor and between 1 and 4
484 gigabytes of physical RAM.
488 depends on X86_CMPXCHG64
490 Select this if you have a 32-bit processor and more than 4
491 gigabytes of physical RAM.
496 depends on EXPERIMENTAL && !X86_PAE
497 prompt "Memory split" if EMBEDDED
500 Select the desired split between kernel and user memory.
502 If the address range available to the kernel is less than the
503 physical memory installed, the remaining memory will be available
504 as "high memory". Accessing high memory is a little more costly
505 than low memory, as it needs to be mapped into the kernel first.
506 Note that increasing the kernel address space limits the range
507 available to user programs, making the address space there
508 tighter. Selecting anything other than the default 3G/1G split
509 will also likely make your kernel incompatible with binary-only
512 If you are not absolutely sure what you are doing, leave this
516 bool "3G/1G user/kernel split"
517 config VMSPLIT_3G_OPT
518 bool "3G/1G user/kernel split (for full 1G low memory)"
520 bool "2G/2G user/kernel split"
522 bool "1G/3G user/kernel split"
527 default 0xB0000000 if VMSPLIT_3G_OPT
528 default 0x78000000 if VMSPLIT_2G
529 default 0x40000000 if VMSPLIT_1G
534 depends on HIGHMEM64G || HIGHMEM4G
539 depends on HIGHMEM64G
541 select RESOURCES_64BIT
543 # Common NUMA Features
545 bool "Numa Memory Allocation and Scheduler Support"
546 depends on SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI)
548 default y if (X86_NUMAQ || X86_SUMMIT)
550 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
551 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
555 default "4" if X86_NUMAQ
557 depends on NEED_MULTIPLE_NODES
559 config HAVE_ARCH_BOOTMEM_NODE
564 config ARCH_HAVE_MEMORY_PRESENT
566 depends on DISCONTIGMEM
569 config NEED_NODE_MEMMAP_SIZE
571 depends on DISCONTIGMEM || SPARSEMEM
574 config HAVE_ARCH_ALLOC_REMAP
579 config ARCH_FLATMEM_ENABLE
581 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
583 config ARCH_DISCONTIGMEM_ENABLE
587 config ARCH_DISCONTIGMEM_DEFAULT
591 config ARCH_SPARSEMEM_ENABLE
593 depends on (NUMA || (X86_PC && EXPERIMENTAL))
594 select SPARSEMEM_STATIC
596 config ARCH_SELECT_MEMORY_MODEL
598 depends on ARCH_SPARSEMEM_ENABLE
602 config HAVE_ARCH_EARLY_PFN_TO_NID
608 bool "Allocate 3rd-level pagetables from highmem"
609 depends on HIGHMEM4G || HIGHMEM64G
611 The VM uses one page table entry for each page of physical memory.
612 For systems with a lot of RAM, this can be wasteful of precious
613 low memory. Setting this option will put user-space page table
614 entries in high memory.
616 config MATH_EMULATION
617 bool "Math emulation"
619 Linux can emulate a math coprocessor (used for floating point
620 operations) if you don't have one. 486DX and Pentium processors have
621 a math coprocessor built in, 486SX and 386 do not, unless you added
622 a 487DX or 387, respectively. (The messages during boot time can
623 give you some hints here ["man dmesg"].) Everyone needs either a
624 coprocessor or this emulation.
626 If you don't have a math coprocessor, you need to say Y here; if you
627 say Y here even though you have a coprocessor, the coprocessor will
628 be used nevertheless. (This behavior can be changed with the kernel
629 command line option "no387", which comes handy if your coprocessor
630 is broken. Try "man bootparam" or see the documentation of your boot
631 loader (lilo or loadlin) about how to pass options to the kernel at
632 boot time.) This means that it is a good idea to say Y here if you
633 intend to use this kernel on different machines.
635 More information about the internals of the Linux math coprocessor
636 emulation can be found in <file:arch/i386/math-emu/README>.
638 If you are not sure, say Y; apart from resulting in a 66 KB bigger
639 kernel, it won't hurt.
642 bool "MTRR (Memory Type Range Register) support"
644 On Intel P6 family processors (Pentium Pro, Pentium II and later)
645 the Memory Type Range Registers (MTRRs) may be used to control
646 processor access to memory ranges. This is most useful if you have
647 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
648 allows bus write transfers to be combined into a larger transfer
649 before bursting over the PCI/AGP bus. This can increase performance
650 of image write operations 2.5 times or more. Saying Y here creates a
651 /proc/mtrr file which may be used to manipulate your processor's
652 MTRRs. Typically the X server should use this.
654 This code has a reasonably generic interface so that similar
655 control registers on other processors can be easily supported
658 The Cyrix 6x86, 6x86MX and M II processors have Address Range
659 Registers (ARRs) which provide a similar functionality to MTRRs. For
660 these, the ARRs are used to emulate the MTRRs.
661 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
662 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
663 write-combining. All of these processors are supported by this code
664 and it makes sense to say Y here if you have one of them.
666 Saying Y here also fixes a problem with buggy SMP BIOSes which only
667 set the MTRRs for the boot CPU and not for the secondary CPUs. This
668 can lead to all sorts of problems, so it's good to say Y here.
670 You can safely say Y even if your machine doesn't have MTRRs, you'll
671 just add about 9 KB to your kernel.
673 See <file:Documentation/mtrr.txt> for more information.
676 bool "Boot from EFI support"
680 This enables the the kernel to boot on EFI platforms using
681 system configuration information passed to it from the firmware.
682 This also enables the kernel to use any EFI runtime services that are
683 available (such as the EFI variable services).
685 This option is only useful on systems that have EFI firmware
686 and will result in a kernel image that is ~8k larger. In addition,
687 you must use the latest ELILO loader available at
688 <http://elilo.sourceforge.net> in order to take advantage of
689 kernel initialization using EFI information (neither GRUB nor LILO know
690 anything about EFI). However, even with this option, the resultant
691 kernel should continue to boot on existing non-EFI platforms.
694 bool "Enable kernel irq balancing"
695 depends on SMP && X86_IO_APIC
698 The default yes will allow the kernel to do irq load balancing.
699 Saying no will keep the kernel from doing irq load balancing.
701 # turning this on wastes a bunch of space.
702 # Summit needs it only when NUMA is on
705 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
709 bool "Use register arguments"
712 Compile the kernel with -mregparm=3. This instructs gcc to use
713 a more efficient function call ABI which passes the first three
714 arguments of a function call via registers, which results in denser
717 If this option is disabled, then the default ABI of passing
718 arguments via the stack is used.
723 bool "Enable seccomp to safely compute untrusted bytecode"
727 This kernel feature is useful for number crunching applications
728 that may need to compute untrusted bytecode during their
729 execution. By using pipes or other transports made available to
730 the process as file descriptors supporting the read/write
731 syscalls, it's possible to isolate those applications in
732 their own address space using seccomp. Once seccomp is
733 enabled via /proc/<pid>/seccomp, it cannot be disabled
734 and the task is only allowed to execute a few safe syscalls
735 defined by each seccomp mode.
737 If unsure, say Y. Only embedded should say N here.
739 source kernel/Kconfig.hz
742 bool "kexec system call (EXPERIMENTAL)"
743 depends on EXPERIMENTAL
745 kexec is a system call that implements the ability to shutdown your
746 current kernel, and to start another kernel. It is like a reboot
747 but it is independent of the system firmware. And like a reboot
748 you can start any kernel with it, not just Linux.
750 The name comes from the similarity to the exec system call.
752 It is an ongoing process to be certain the hardware in a machine
753 is properly shutdown, so do not be surprised if this code does not
754 initially work for you. It may help to enable device hotplugging
755 support. As of this writing the exact hardware interface is
756 strongly in flux, so no good recommendation can be made.
759 bool "kernel crash dumps (EXPERIMENTAL)"
760 depends on EXPERIMENTAL
763 Generate crash dump after being started by kexec.
764 This should be normally only set in special crash dump kernels
765 which are loaded in the main kernel with kexec-tools into
766 a specially reserved region and then later executed after
767 a crash by kdump/kexec. The crash dump kernel must be compiled
768 to a memory address not used by the main kernel or BIOS using
770 For more details see Documentation/kdump/kdump.txt
772 config PHYSICAL_START
773 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
775 default "0x1000000" if CRASH_DUMP
778 This gives the physical address where the kernel is loaded. Normally
779 for regular kernels this value is 0x100000 (1MB). But in the case
780 of kexec on panic the fail safe kernel needs to run at a different
781 address than the panic-ed kernel. This option is used to set the load
782 address for kernels used to capture crash dump on being kexec'ed
783 after panic. The default value for crash dump kernels is
784 0x1000000 (16MB). This can also be set based on the "X" value as
785 specified in the "crashkernel=YM@XM" command line boot parameter
786 passed to the panic-ed kernel. Typically this parameter is set as
787 crashkernel=64M@16M. Please take a look at
788 Documentation/kdump/kdump.txt for more details about crash dumps.
790 Don't change this unless you know what you are doing.
793 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
794 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
796 Say Y here to experiment with turning CPUs off and on, and to
797 enable suspend on SMP systems. CPUs can be controlled through
798 /sys/devices/system/cpu.
801 bool "Compat VDSO support"
804 Map the VDSO to the predictable old-style address too.
806 Say N here if you are running a sufficiently recent glibc
807 version (2.3.3 or later), to remove the high-mapped
808 VDSO mapping and to exclusively use the randomized VDSO.
814 config ARCH_ENABLE_MEMORY_HOTPLUG
818 menu "Power management options (ACPI, APM)"
819 depends on !X86_VOYAGER
821 source kernel/power/Kconfig
823 source "drivers/acpi/Kconfig"
825 menu "APM (Advanced Power Management) BIOS Support"
826 depends on PM && !X86_VISWS
829 tristate "APM (Advanced Power Management) BIOS support"
832 APM is a BIOS specification for saving power using several different
833 techniques. This is mostly useful for battery powered laptops with
834 APM compliant BIOSes. If you say Y here, the system time will be
835 reset after a RESUME operation, the /proc/apm device will provide
836 battery status information, and user-space programs will receive
837 notification of APM "events" (e.g. battery status change).
839 If you select "Y" here, you can disable actual use of the APM
840 BIOS by passing the "apm=off" option to the kernel at boot time.
842 Note that the APM support is almost completely disabled for
843 machines with more than one CPU.
845 In order to use APM, you will need supporting software. For location
846 and more information, read <file:Documentation/pm.txt> and the
847 Battery Powered Linux mini-HOWTO, available from
848 <http://www.tldp.org/docs.html#howto>.
850 This driver does not spin down disk drives (see the hdparm(8)
851 manpage ("man 8 hdparm") for that), and it doesn't turn off
852 VESA-compliant "green" monitors.
854 This driver does not support the TI 4000M TravelMate and the ACER
855 486/DX4/75 because they don't have compliant BIOSes. Many "green"
856 desktop machines also don't have compliant BIOSes, and this driver
857 may cause those machines to panic during the boot phase.
859 Generally, if you don't have a battery in your machine, there isn't
860 much point in using this driver and you should say N. If you get
861 random kernel OOPSes or reboots that don't seem to be related to
862 anything, try disabling/enabling this option (or disabling/enabling
865 Some other things you should try when experiencing seemingly random,
868 1) make sure that you have enough swap space and that it is
870 2) pass the "no-hlt" option to the kernel
871 3) switch on floating point emulation in the kernel and pass
872 the "no387" option to the kernel
873 4) pass the "floppy=nodma" option to the kernel
874 5) pass the "mem=4M" option to the kernel (thereby disabling
875 all but the first 4 MB of RAM)
876 6) make sure that the CPU is not over clocked.
877 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
878 8) disable the cache from your BIOS settings
879 9) install a fan for the video card or exchange video RAM
880 10) install a better fan for the CPU
881 11) exchange RAM chips
882 12) exchange the motherboard.
884 To compile this driver as a module, choose M here: the
885 module will be called apm.
887 config APM_IGNORE_USER_SUSPEND
888 bool "Ignore USER SUSPEND"
891 This option will ignore USER SUSPEND requests. On machines with a
892 compliant APM BIOS, you want to say N. However, on the NEC Versa M
893 series notebooks, it is necessary to say Y because of a BIOS bug.
896 bool "Enable PM at boot time"
899 Enable APM features at boot time. From page 36 of the APM BIOS
900 specification: "When disabled, the APM BIOS does not automatically
901 power manage devices, enter the Standby State, enter the Suspend
902 State, or take power saving steps in response to CPU Idle calls."
903 This driver will make CPU Idle calls when Linux is idle (unless this
904 feature is turned off -- see "Do CPU IDLE calls", below). This
905 should always save battery power, but more complicated APM features
906 will be dependent on your BIOS implementation. You may need to turn
907 this option off if your computer hangs at boot time when using APM
908 support, or if it beeps continuously instead of suspending. Turn
909 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
910 T400CDT. This is off by default since most machines do fine without
914 bool "Make CPU Idle calls when idle"
917 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
918 On some machines, this can activate improved power savings, such as
919 a slowed CPU clock rate, when the machine is idle. These idle calls
920 are made after the idle loop has run for some length of time (e.g.,
921 333 mS). On some machines, this will cause a hang at boot time or
922 whenever the CPU becomes idle. (On machines with more than one CPU,
923 this option does nothing.)
925 config APM_DISPLAY_BLANK
926 bool "Enable console blanking using APM"
929 Enable console blanking using the APM. Some laptops can use this to
930 turn off the LCD backlight when the screen blanker of the Linux
931 virtual console blanks the screen. Note that this is only used by
932 the virtual console screen blanker, and won't turn off the backlight
933 when using the X Window system. This also doesn't have anything to
934 do with your VESA-compliant power-saving monitor. Further, this
935 option doesn't work for all laptops -- it might not turn off your
936 backlight at all, or it might print a lot of errors to the console,
937 especially if you are using gpm.
939 config APM_RTC_IS_GMT
940 bool "RTC stores time in GMT"
943 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
944 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
947 It is in fact recommended to store GMT in your RTC, because then you
948 don't have to worry about daylight savings time changes. The only
949 reason not to use GMT in your RTC is if you also run a broken OS
950 that doesn't understand GMT.
952 config APM_ALLOW_INTS
953 bool "Allow interrupts during APM BIOS calls"
956 Normally we disable external interrupts while we are making calls to
957 the APM BIOS as a measure to lessen the effects of a badly behaving
958 BIOS implementation. The BIOS should reenable interrupts if it
959 needs to. Unfortunately, some BIOSes do not -- especially those in
960 many of the newer IBM Thinkpads. If you experience hangs when you
961 suspend, try setting this to Y. Otherwise, say N.
963 config APM_REAL_MODE_POWER_OFF
964 bool "Use real mode APM BIOS call to power off"
967 Use real mode APM BIOS calls to switch off the computer. This is
968 a work-around for a number of buggy BIOSes. Switch this option on if
969 your computer crashes instead of powering off properly.
973 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
977 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
980 bool "PCI support" if !X86_VISWS
981 depends on !X86_VOYAGER
982 default y if X86_VISWS
984 Find out whether you have a PCI motherboard. PCI is the name of a
985 bus system, i.e. the way the CPU talks to the other stuff inside
986 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
987 VESA. If you have PCI, say Y, otherwise N.
989 The PCI-HOWTO, available from
990 <http://www.tldp.org/docs.html#howto>, contains valuable
991 information about which PCI hardware does work under Linux and which
995 prompt "PCI access mode"
996 depends on PCI && !X86_VISWS
999 On PCI systems, the BIOS can be used to detect the PCI devices and
1000 determine their configuration. However, some old PCI motherboards
1001 have BIOS bugs and may crash if this is done. Also, some embedded
1002 PCI-based systems don't have any BIOS at all. Linux can also try to
1003 detect the PCI hardware directly without using the BIOS.
1005 With this option, you can specify how Linux should detect the
1006 PCI devices. If you choose "BIOS", the BIOS will be used,
1007 if you choose "Direct", the BIOS won't be used, and if you
1008 choose "MMConfig", then PCI Express MMCONFIG will be used.
1009 If you choose "Any", the kernel will try MMCONFIG, then the
1010 direct access method and falls back to the BIOS if that doesn't
1011 work. If unsure, go with the default, which is "Any".
1016 config PCI_GOMMCONFIG
1029 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1034 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1039 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1042 source "drivers/pci/pcie/Kconfig"
1044 source "drivers/pci/Kconfig"
1052 depends on !(X86_VOYAGER || X86_VISWS)
1054 Find out whether you have ISA slots on your motherboard. ISA is the
1055 name of a bus system, i.e. the way the CPU talks to the other stuff
1056 inside your box. Other bus systems are PCI, EISA, MicroChannel
1057 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1058 newer boards don't support it. If you have ISA, say Y, otherwise N.
1064 The Extended Industry Standard Architecture (EISA) bus was
1065 developed as an open alternative to the IBM MicroChannel bus.
1067 The EISA bus provided some of the features of the IBM MicroChannel
1068 bus while maintaining backward compatibility with cards made for
1069 the older ISA bus. The EISA bus saw limited use between 1988 and
1070 1995 when it was made obsolete by the PCI bus.
1072 Say Y here if you are building a kernel for an EISA-based machine.
1076 source "drivers/eisa/Kconfig"
1079 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1080 default y if X86_VOYAGER
1082 MicroChannel Architecture is found in some IBM PS/2 machines and
1083 laptops. It is a bus system similar to PCI or ISA. See
1084 <file:Documentation/mca.txt> (and especially the web page given
1085 there) before attempting to build an MCA bus kernel.
1087 source "drivers/mca/Kconfig"
1090 tristate "NatSemi SCx200 support"
1091 depends on !X86_VOYAGER
1093 This provides basic support for National Semiconductor's
1094 (now AMD's) Geode processors. The driver probes for the
1095 PCI-IDs of several on-chip devices, so its a good dependency
1096 for other scx200_* drivers.
1098 If compiled as a module, the driver is named scx200.
1100 config SCx200HR_TIMER
1101 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1102 depends on SCx200 && GENERIC_TIME
1105 This driver provides a clocksource built upon the on-chip
1106 27MHz high-resolution timer. Its also a workaround for
1107 NSC Geode SC-1100's buggy TSC, which loses time when the
1108 processor goes idle (as is done by the scheduler). The
1109 other workaround is idle=poll boot option.
1113 depends on AGP_AMD64
1115 source "drivers/pcmcia/Kconfig"
1117 source "drivers/pci/hotplug/Kconfig"
1121 menu "Executable file formats"
1123 source "fs/Kconfig.binfmt"
1127 source "net/Kconfig"
1129 source "drivers/Kconfig"
1133 menu "Instrumentation Support"
1134 depends on EXPERIMENTAL
1136 source "arch/i386/oprofile/Kconfig"
1139 bool "Kprobes (EXPERIMENTAL)"
1140 depends on EXPERIMENTAL && MODULES
1142 Kprobes allows you to trap at almost any kernel address and
1143 execute a callback function. register_kprobe() establishes
1144 a probepoint and specifies the callback. Kprobes is useful
1145 for kernel debugging, non-intrusive instrumentation and testing.
1146 If in doubt, say "N".
1149 source "arch/i386/Kconfig.debug"
1151 source "security/Kconfig"
1153 source "crypto/Kconfig"
1155 source "lib/Kconfig"
1158 # Use the generic interrupt handling code in kernel/irq/:
1160 config GENERIC_HARDIRQS
1164 config GENERIC_IRQ_PROBE
1168 config GENERIC_PENDING_IRQ
1170 depends on GENERIC_HARDIRQS && SMP
1175 depends on SMP && !X86_VOYAGER
1180 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1183 config X86_BIOS_REBOOT
1185 depends on !(X86_VISWS || X86_VOYAGER)
1188 config X86_TRAMPOLINE
1190 depends on X86_SMP || (X86_VOYAGER && SMP)
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