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 - "CyrixIII/VIA C3" for VIA Cyrix III or VIA C3.
187 - "VIA C3-2 for VIA C3-2 "Nehemiah" (model 9 and above).
189 If you don't know what to do, choose "386".
194 Select this for a 486 series processor, either Intel or one of the
195 compatible processors from AMD, Cyrix, IBM, or Intel. Includes DX,
196 DX2, and DX4 variants; also SL/SLC/SLC2/SLC3/SX/SX2 and UMC U5D or
200 bool "586/K5/5x86/6x86/6x86MX"
202 Select this for an 586 or 686 series processor such as the AMD K5,
203 the Cyrix 5x86, 6x86 and 6x86MX. This choice does not
204 assume the RDTSC (Read Time Stamp Counter) instruction.
207 bool "Pentium-Classic"
209 Select this for a Pentium Classic processor with the RDTSC (Read
210 Time Stamp Counter) instruction for benchmarking.
215 Select this for a Pentium with the MMX graphics/multimedia
216 extended instructions.
221 Select this for Intel Pentium Pro chips. This enables the use of
222 Pentium Pro extended instructions, and disables the init-time guard
223 against the f00f bug found in earlier Pentiums.
226 bool "Pentium-II/Celeron(pre-Coppermine)"
228 Select this for Intel chips based on the Pentium-II and
229 pre-Coppermine Celeron core. This option enables an unaligned
230 copy optimization, compiles the kernel with optimization flags
231 tailored for the chip, and applies any applicable Pentium Pro
235 bool "Pentium-III/Celeron(Coppermine)/Pentium-III Xeon"
237 Select this for Intel chips based on the Pentium-III and
238 Celeron-Coppermine core. This option enables use of some
239 extended prefetch instructions in addition to the Pentium II
245 Select this for Intel Pentium M (not Pentium-4 M)
249 bool "Pentium-4/Celeron(P4-based)/Pentium-4 M/Xeon"
251 Select this for Intel Pentium 4 chips. This includes the
252 Pentium 4, P4-based Celeron and Xeon, and Pentium-4 M
253 (not Pentium M) chips. This option enables compile flags
254 optimized for the chip, uses the correct cache shift, and
255 applies any applicable Pentium III optimizations.
258 bool "K6/K6-II/K6-III"
260 Select this for an AMD K6-family processor. Enables use of
261 some extended instructions, and passes appropriate optimization
265 bool "Athlon/Duron/K7"
267 Select this for an AMD Athlon K7-family processor. Enables use of
268 some extended instructions, and passes appropriate optimization
272 bool "Opteron/Athlon64/Hammer/K8"
274 Select this for an AMD Opteron or Athlon64 Hammer-family processor. Enables
275 use of some extended instructions, and passes appropriate optimization
281 Select this for a Transmeta Crusoe processor. Treats the processor
282 like a 586 with TSC, and sets some GCC optimization flags (like a
283 Pentium Pro with no alignment requirements).
288 Select this for a Transmeta Efficeon processor.
293 Select this for an IDT Winchip C6 chip. Linux and GCC
294 treat this chip as a 586TSC with some extended instructions
295 and alignment requirements.
300 Select this for an IDT Winchip-2. Linux and GCC
301 treat this chip as a 586TSC with some extended instructions
302 and alignment requirements.
305 bool "Winchip-2A/Winchip-3"
307 Select this for an IDT Winchip-2A or 3. Linux and GCC
308 treat this chip as a 586TSC with some extended instructions
309 and alignment reqirements. Also enable out of order memory
310 stores for this CPU, which can increase performance of some
314 bool "CyrixIII/VIA-C3"
316 Select this for a Cyrix III or C3 chip. Presently Linux and GCC
317 treat this chip as a generic 586. Whilst the CPU is 686 class,
318 it lacks the cmov extension which gcc assumes is present when
320 Note that Nehemiah (Model 9) and above will not boot with this
321 kernel due to them lacking the 3DNow! instructions used in earlier
322 incarnations of the CPU.
325 bool "VIA C3-2 (Nehemiah)"
327 Select this for a VIA C3 "Nehemiah". Selecting this enables usage
328 of SSE and tells gcc to treat the CPU as a 686.
329 Note, this kernel will not boot on older (pre model 9) C3s.
334 bool "Generic x86 support"
336 Instead of just including optimizations for the selected
337 x86 variant (e.g. PII, Crusoe or Athlon), include some more
338 generic optimizations as well. This will make the kernel
339 perform better on x86 CPUs other than that selected.
341 This is really intended for distributors who need more
342 generic optimizations.
347 # Define implied options from the CPU selection here
359 config X86_L1_CACHE_SHIFT
361 default "7" if MPENTIUM4 || X86_GENERIC
362 default "4" if X86_ELAN || M486 || M386
363 default "5" if MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCRUSOE || MEFFICEON || MCYRIXIII || MK6 || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || M586 || MVIAC3_2
364 default "6" if MK7 || MK8 || MPENTIUMM
366 config RWSEM_GENERIC_SPINLOCK
371 config RWSEM_XCHGADD_ALGORITHM
376 config X86_PPRO_FENCE
378 depends on M686 || M586MMX || M586TSC || M586 || M486 || M386
383 depends on M586MMX || M586TSC || M586 || M486 || M386
386 config X86_WP_WORKS_OK
406 config X86_ALIGNMENT_16
408 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || X86_ELAN || MK6 || M586MMX || M586TSC || M586 || M486 || MVIAC3_2
413 depends on MK7 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || MK8 || MEFFICEON
416 config X86_INTEL_USERCOPY
418 depends on MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M586MMX || X86_GENERIC || MK8 || MK7 || MEFFICEON
421 config X86_USE_PPRO_CHECKSUM
423 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC3_2 || MEFFICEON
428 depends on MCYRIXIII || MK7
433 depends on (MWINCHIP3D || MWINCHIP2 || MWINCHIPC6) && MTRR
437 bool "HPET Timer Support"
439 This enables the use of the HPET for the kernel's internal timer.
440 HPET is the next generation timer replacing legacy 8254s.
441 You can safely choose Y here. However, HPET will only be
442 activated if the platform and the BIOS support this feature.
443 Otherwise the 8254 will be used for timing services.
445 Choose N to continue using the legacy 8254 timer.
447 config HPET_EMULATE_RTC
448 bool "Provide RTC interrupt"
449 depends on HPET_TIMER && RTC=y
452 bool "Symmetric multi-processing support"
454 This enables support for systems with more than one CPU. If you have
455 a system with only one CPU, like most personal computers, say N. If
456 you have a system with more than one CPU, say Y.
458 If you say N here, the kernel will run on single and multiprocessor
459 machines, but will use only one CPU of a multiprocessor machine. If
460 you say Y here, the kernel will run on many, but not all,
461 singleprocessor machines. On a singleprocessor machine, the kernel
462 will run faster if you say N here.
464 Note that if you say Y here and choose architecture "586" or
465 "Pentium" under "Processor family", the kernel will not work on 486
466 architectures. Similarly, multiprocessor kernels for the "PPro"
467 architecture may not work on all Pentium based boards.
469 People using multiprocessor machines who say Y here should also say
470 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
471 Management" code will be disabled if you say Y here.
473 See also the <file:Documentation/smp.txt>,
474 <file:Documentation/i386/IO-APIC.txt>,
475 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
476 <http://www.tldp.org/docs.html#howto>.
478 If you don't know what to do here, say N.
481 int "Maximum number of CPUs (2-255)"
484 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
487 This allows you to specify the maximum number of CPUs which this
488 kernel will support. The maximum supported value is 255 and the
489 minimum value which makes sense is 2.
491 This is purely to save memory - each supported CPU adds
492 approximately eight kilobytes to the kernel image.
495 bool "SMT (Hyperthreading) scheduler support"
499 SMT scheduler support improves the CPU scheduler's decision making
500 when dealing with Intel Pentium 4 chips with HyperThreading at a
501 cost of slightly increased overhead in some places. If unsure say
505 bool "Preemptible Kernel"
507 This option reduces the latency of the kernel when reacting to
508 real-time or interactive events by allowing a low priority process to
509 be preempted even if it is in kernel mode executing a system call.
510 This allows applications to run more reliably even when the system is
513 Say Y here if you are building a kernel for a desktop, embedded
514 or real-time system. Say N if you are unsure.
517 bool "Local APIC support on uniprocessors" if !SMP
518 depends on !(X86_VISWS || X86_VOYAGER)
520 A local APIC (Advanced Programmable Interrupt Controller) is an
521 integrated interrupt controller in the CPU. If you have a single-CPU
522 system which has a processor with a local APIC, you can say Y here to
523 enable and use it. If you say Y here even though your machine doesn't
524 have a local APIC, then the kernel will still run with no slowdown at
525 all. The local APIC supports CPU-generated self-interrupts (timer,
526 performance counters), and the NMI watchdog which detects hard
529 If you have a system with several CPUs, you do not need to say Y
530 here: the local APIC will be used automatically.
533 bool "IO-APIC support on uniprocessors"
534 depends on !SMP && X86_UP_APIC
536 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
537 SMP-capable replacement for PC-style interrupt controllers. Most
538 SMP systems and a small number of uniprocessor systems have one.
539 If you have a single-CPU system with an IO-APIC, you can say Y here
540 to use it. If you say Y here even though your machine doesn't have
541 an IO-APIC, then the kernel will still run with no slowdown at all.
543 If you have a system with several CPUs, you do not need to say Y
544 here: the IO-APIC will be used automatically.
546 config X86_LOCAL_APIC
548 depends on !SMP && X86_UP_APIC
553 depends on !SMP && X86_UP_IOAPIC
558 depends on (MWINCHIP3D || MWINCHIP2 || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2) && !X86_NUMAQ
562 bool "Machine Check Exception"
563 depends on !X86_VOYAGER
565 Machine Check Exception support allows the processor to notify the
566 kernel if it detects a problem (e.g. overheating, component failure).
567 The action the kernel takes depends on the severity of the problem,
568 ranging from a warning message on the console, to halting the machine.
569 Your processor must be a Pentium or newer to support this - check the
570 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
571 have a design flaw which leads to false MCE events - hence MCE is
572 disabled on all P5 processors, unless explicitly enabled with "mce"
573 as a boot argument. Similarly, if MCE is built in and creates a
574 problem on some new non-standard machine, you can boot with "nomce"
575 to disable it. MCE support simply ignores non-MCE processors like
576 the 386 and 486, so nearly everyone can say Y here.
578 config X86_MCE_NONFATAL
579 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
582 Enabling this feature starts a timer that triggers every 5 seconds which
583 will look at the machine check registers to see if anything happened.
584 Non-fatal problems automatically get corrected (but still logged).
585 Disable this if you don't want to see these messages.
586 Seeing the messages this option prints out may be indicative of dying hardware,
587 or out-of-spec (ie, overclocked) hardware.
588 This option only does something on certain CPUs.
589 (AMD Athlon/Duron and Intel Pentium 4)
591 config X86_MCE_P4THERMAL
592 bool "check for P4 thermal throttling interrupt."
593 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
595 Enabling this feature will cause a message to be printed when the P4
596 enters thermal throttling.
599 tristate "Toshiba Laptop support"
601 This adds a driver to safely access the System Management Mode of
602 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
603 not work on models with a Phoenix BIOS. The System Management Mode
604 is used to set the BIOS and power saving options on Toshiba portables.
606 For information on utilities to make use of this driver see the
607 Toshiba Linux utilities web site at:
608 <http://www.buzzard.org.uk/toshiba/>.
610 Say Y if you intend to run this kernel on a Toshiba portable.
614 tristate "Dell laptop support"
616 This adds a driver to safely access the System Management Mode
617 of the CPU on the Dell Inspiron 8000. The System Management Mode
618 is used to read cpu temperature and cooling fan status and to
619 control the fans on the I8K portables.
621 This driver has been tested only on the Inspiron 8000 but it may
622 also work with other Dell laptops. You can force loading on other
623 models by passing the parameter `force=1' to the module. Use at
626 For information on utilities to make use of this driver see the
627 I8K Linux utilities web site at:
628 <http://people.debian.org/~dz/i8k/>
630 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
634 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
636 If you say Y here and also to "/dev file system support" in the
637 'File systems' section, you will be able to update the microcode on
638 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
639 Pentium III, Pentium 4, Xeon etc. You will obviously need the
640 actual microcode binary data itself which is not shipped with the
643 For latest news and information on obtaining all the required
644 ingredients for this driver, check:
645 <http://www.urbanmyth.org/microcode/>.
647 To compile this driver as a module, choose M here: the
648 module will be called microcode.
651 tristate "/dev/cpu/*/msr - Model-specific register support"
653 This device gives privileged processes access to the x86
654 Model-Specific Registers (MSRs). It is a character device with
655 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
656 MSR accesses are directed to a specific CPU on multi-processor
660 tristate "/dev/cpu/*/cpuid - CPU information support"
662 This device gives processes access to the x86 CPUID instruction to
663 be executed on a specific processor. It is a character device
664 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
667 source "drivers/firmware/Kconfig"
670 prompt "High Memory Support"
676 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
677 However, the address space of 32-bit x86 processors is only 4
678 Gigabytes large. That means that, if you have a large amount of
679 physical memory, not all of it can be "permanently mapped" by the
680 kernel. The physical memory that's not permanently mapped is called
683 If you are compiling a kernel which will never run on a machine with
684 more than 1 Gigabyte total physical RAM, answer "off" here (default
685 choice and suitable for most users). This will result in a "3GB/1GB"
686 split: 3GB are mapped so that each process sees a 3GB virtual memory
687 space and the remaining part of the 4GB virtual memory space is used
688 by the kernel to permanently map as much physical memory as
691 If the machine has between 1 and 4 Gigabytes physical RAM, then
694 If more than 4 Gigabytes is used then answer "64GB" here. This
695 selection turns Intel PAE (Physical Address Extension) mode on.
696 PAE implements 3-level paging on IA32 processors. PAE is fully
697 supported by Linux, PAE mode is implemented on all recent Intel
698 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
699 then the kernel will not boot on CPUs that don't support PAE!
701 The actual amount of total physical memory will either be
702 auto detected or can be forced by using a kernel command line option
703 such as "mem=256M". (Try "man bootparam" or see the documentation of
704 your boot loader (lilo or loadlin) about how to pass options to the
705 kernel at boot time.)
707 If unsure, say "off".
712 Select this if you have a 32-bit processor and between 1 and 4
713 gigabytes of physical RAM.
718 Select this if you have a 32-bit processor and more than 4
719 gigabytes of physical RAM.
725 depends on HIGHMEM64G || HIGHMEM4G
730 depends on HIGHMEM64G
733 # Common NUMA Features
735 bool "Numa Memory Allocation and Scheduler Support"
736 depends on SMP && HIGHMEM64G && (X86_NUMAQ || X86_GENERICARCH || (X86_SUMMIT && ACPI))
738 default y if (X86_NUMAQ || X86_SUMMIT)
740 # Need comments to help the hapless user trying to turn on NUMA support
741 comment "NUMA (NUMA-Q) requires SMP, 64GB highmem support"
742 depends on X86_NUMAQ && (!HIGHMEM64G || !SMP)
744 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
745 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
752 config HAVE_ARCH_BOOTMEM_NODE
758 bool "Allocate 3rd-level pagetables from highmem"
759 depends on HIGHMEM4G || HIGHMEM64G
761 The VM uses one page table entry for each page of physical memory.
762 For systems with a lot of RAM, this can be wasteful of precious
763 low memory. Setting this option will put user-space page table
764 entries in high memory.
766 config MATH_EMULATION
767 bool "Math emulation"
769 Linux can emulate a math coprocessor (used for floating point
770 operations) if you don't have one. 486DX and Pentium processors have
771 a math coprocessor built in, 486SX and 386 do not, unless you added
772 a 487DX or 387, respectively. (The messages during boot time can
773 give you some hints here ["man dmesg"].) Everyone needs either a
774 coprocessor or this emulation.
776 If you don't have a math coprocessor, you need to say Y here; if you
777 say Y here even though you have a coprocessor, the coprocessor will
778 be used nevertheless. (This behavior can be changed with the kernel
779 command line option "no387", which comes handy if your coprocessor
780 is broken. Try "man bootparam" or see the documentation of your boot
781 loader (lilo or loadlin) about how to pass options to the kernel at
782 boot time.) This means that it is a good idea to say Y here if you
783 intend to use this kernel on different machines.
785 More information about the internals of the Linux math coprocessor
786 emulation can be found in <file:arch/i386/math-emu/README>.
788 If you are not sure, say Y; apart from resulting in a 66 KB bigger
789 kernel, it won't hurt.
792 bool "MTRR (Memory Type Range Register) support"
794 On Intel P6 family processors (Pentium Pro, Pentium II and later)
795 the Memory Type Range Registers (MTRRs) may be used to control
796 processor access to memory ranges. This is most useful if you have
797 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
798 allows bus write transfers to be combined into a larger transfer
799 before bursting over the PCI/AGP bus. This can increase performance
800 of image write operations 2.5 times or more. Saying Y here creates a
801 /proc/mtrr file which may be used to manipulate your processor's
802 MTRRs. Typically the X server should use this.
804 This code has a reasonably generic interface so that similar
805 control registers on other processors can be easily supported
808 The Cyrix 6x86, 6x86MX and M II processors have Address Range
809 Registers (ARRs) which provide a similar functionality to MTRRs. For
810 these, the ARRs are used to emulate the MTRRs.
811 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
812 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
813 write-combining. All of these processors are supported by this code
814 and it makes sense to say Y here if you have one of them.
816 Saying Y here also fixes a problem with buggy SMP BIOSes which only
817 set the MTRRs for the boot CPU and not for the secondary CPUs. This
818 can lead to all sorts of problems, so it's good to say Y here.
820 You can safely say Y even if your machine doesn't have MTRRs, you'll
821 just add about 9 KB to your kernel.
823 See <file:Documentation/mtrr.txt> for more information.
826 bool "Boot from EFI support (EXPERIMENTAL)"
831 This enables the the kernel to boot on EFI platforms using
832 system configuration information passed to it from the firmware.
833 This also enables the kernel to use any EFI runtime services that are
834 available (such as the EFI variable services).
836 This option is only useful on systems that have EFI firmware
837 and will result in a kernel image that is ~8k larger. In addition,
838 you must use the latest ELILO loader available at
839 <http://elilo.sourceforge.net> in order to take advantage of
840 kernel initialization using EFI information (neither GRUB nor LILO know
841 anything about EFI). However, even with this option, the resultant
842 kernel should continue to boot on existing non-EFI platforms.
845 bool "Enable kernel irq balancing"
846 depends on SMP && X86_IO_APIC
849 The default yes will allow the kernel to do irq load balancing.
850 Saying no will keep the kernel from doing irq load balancing.
854 depends on (SMP || PREEMPT) && X86_CMPXCHG
857 # turning this on wastes a bunch of space.
858 # Summit needs it only when NUMA is on
861 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
865 bool "Use register arguments (EXPERIMENTAL)"
866 depends on EXPERIMENTAL
869 Compile the kernel with -mregparm=3. This uses an different ABI
870 and passes the first three arguments of a function call in registers.
871 This will probably break binary only modules.
873 This feature is only enabled for gcc-3.0 and later - earlier compilers
874 generate incorrect output with certain kernel constructs when
880 menu "Power management options (ACPI, APM)"
881 depends on !X86_VOYAGER
883 source kernel/power/Kconfig
885 source "drivers/acpi/Kconfig"
887 menu "APM (Advanced Power Management) BIOS Support"
888 depends on PM && !X86_VISWS
891 tristate "APM (Advanced Power Management) BIOS support"
894 APM is a BIOS specification for saving power using several different
895 techniques. This is mostly useful for battery powered laptops with
896 APM compliant BIOSes. If you say Y here, the system time will be
897 reset after a RESUME operation, the /proc/apm device will provide
898 battery status information, and user-space programs will receive
899 notification of APM "events" (e.g. battery status change).
901 If you select "Y" here, you can disable actual use of the APM
902 BIOS by passing the "apm=off" option to the kernel at boot time.
904 Note that the APM support is almost completely disabled for
905 machines with more than one CPU.
907 In order to use APM, you will need supporting software. For location
908 and more information, read <file:Documentation/pm.txt> and the
909 Battery Powered Linux mini-HOWTO, available from
910 <http://www.tldp.org/docs.html#howto>.
912 This driver does not spin down disk drives (see the hdparm(8)
913 manpage ("man 8 hdparm") for that), and it doesn't turn off
914 VESA-compliant "green" monitors.
916 This driver does not support the TI 4000M TravelMate and the ACER
917 486/DX4/75 because they don't have compliant BIOSes. Many "green"
918 desktop machines also don't have compliant BIOSes, and this driver
919 may cause those machines to panic during the boot phase.
921 Generally, if you don't have a battery in your machine, there isn't
922 much point in using this driver and you should say N. If you get
923 random kernel OOPSes or reboots that don't seem to be related to
924 anything, try disabling/enabling this option (or disabling/enabling
927 Some other things you should try when experiencing seemingly random,
930 1) make sure that you have enough swap space and that it is
932 2) pass the "no-hlt" option to the kernel
933 3) switch on floating point emulation in the kernel and pass
934 the "no387" option to the kernel
935 4) pass the "floppy=nodma" option to the kernel
936 5) pass the "mem=4M" option to the kernel (thereby disabling
937 all but the first 4 MB of RAM)
938 6) make sure that the CPU is not over clocked.
939 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
940 8) disable the cache from your BIOS settings
941 9) install a fan for the video card or exchange video RAM
942 10) install a better fan for the CPU
943 11) exchange RAM chips
944 12) exchange the motherboard.
946 To compile this driver as a module, choose M here: the
947 module will be called apm.
949 config APM_IGNORE_USER_SUSPEND
950 bool "Ignore USER SUSPEND"
953 This option will ignore USER SUSPEND requests. On machines with a
954 compliant APM BIOS, you want to say N. However, on the NEC Versa M
955 series notebooks, it is necessary to say Y because of a BIOS bug.
958 bool "Enable PM at boot time"
961 Enable APM features at boot time. From page 36 of the APM BIOS
962 specification: "When disabled, the APM BIOS does not automatically
963 power manage devices, enter the Standby State, enter the Suspend
964 State, or take power saving steps in response to CPU Idle calls."
965 This driver will make CPU Idle calls when Linux is idle (unless this
966 feature is turned off -- see "Do CPU IDLE calls", below). This
967 should always save battery power, but more complicated APM features
968 will be dependent on your BIOS implementation. You may need to turn
969 this option off if your computer hangs at boot time when using APM
970 support, or if it beeps continuously instead of suspending. Turn
971 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
972 T400CDT. This is off by default since most machines do fine without
976 bool "Make CPU Idle calls when idle"
979 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
980 On some machines, this can activate improved power savings, such as
981 a slowed CPU clock rate, when the machine is idle. These idle calls
982 are made after the idle loop has run for some length of time (e.g.,
983 333 mS). On some machines, this will cause a hang at boot time or
984 whenever the CPU becomes idle. (On machines with more than one CPU,
985 this option does nothing.)
987 config APM_DISPLAY_BLANK
988 bool "Enable console blanking using APM"
991 Enable console blanking using the APM. Some laptops can use this to
992 turn off the LCD backlight when the screen blanker of the Linux
993 virtual console blanks the screen. Note that this is only used by
994 the virtual console screen blanker, and won't turn off the backlight
995 when using the X Window system. This also doesn't have anything to
996 do with your VESA-compliant power-saving monitor. Further, this
997 option doesn't work for all laptops -- it might not turn off your
998 backlight at all, or it might print a lot of errors to the console,
999 especially if you are using gpm.
1001 config APM_RTC_IS_GMT
1002 bool "RTC stores time in GMT"
1005 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
1006 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
1009 It is in fact recommended to store GMT in your RTC, because then you
1010 don't have to worry about daylight savings time changes. The only
1011 reason not to use GMT in your RTC is if you also run a broken OS
1012 that doesn't understand GMT.
1014 config APM_ALLOW_INTS
1015 bool "Allow interrupts during APM BIOS calls"
1018 Normally we disable external interrupts while we are making calls to
1019 the APM BIOS as a measure to lessen the effects of a badly behaving
1020 BIOS implementation. The BIOS should reenable interrupts if it
1021 needs to. Unfortunately, some BIOSes do not -- especially those in
1022 many of the newer IBM Thinkpads. If you experience hangs when you
1023 suspend, try setting this to Y. Otherwise, say N.
1025 config APM_REAL_MODE_POWER_OFF
1026 bool "Use real mode APM BIOS call to power off"
1029 Use real mode APM BIOS calls to switch off the computer. This is
1030 a work-around for a number of buggy BIOSes. Switch this option on if
1031 your computer crashes instead of powering off properly.
1035 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1039 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1041 config X86_VISWS_APIC
1043 depends on X86_VISWS
1046 config X86_LOCAL_APIC
1048 depends on (X86_VISWS || SMP) && !X86_VOYAGER
1053 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1057 bool "PCI support" if !X86_VISWS
1058 depends on !X86_VOYAGER
1059 default y if X86_VISWS
1061 Find out whether you have a PCI motherboard. PCI is the name of a
1062 bus system, i.e. the way the CPU talks to the other stuff inside
1063 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1064 VESA. If you have PCI, say Y, otherwise N.
1066 The PCI-HOWTO, available from
1067 <http://www.tldp.org/docs.html#howto>, contains valuable
1068 information about which PCI hardware does work under Linux and which
1072 prompt "PCI access mode"
1073 depends on PCI && !X86_VISWS
1076 On PCI systems, the BIOS can be used to detect the PCI devices and
1077 determine their configuration. However, some old PCI motherboards
1078 have BIOS bugs and may crash if this is done. Also, some embedded
1079 PCI-based systems don't have any BIOS at all. Linux can also try to
1080 detect the PCI hardware directly without using the BIOS.
1082 With this option, you can specify how Linux should detect the
1083 PCI devices. If you choose "BIOS", the BIOS will be used,
1084 if you choose "Direct", the BIOS won't be used, and if you
1085 choose "MMConfig", then PCI Express MMCONFIG will be used.
1086 If you choose "Any", the kernel will try MMCONFIG, then the
1087 direct access method and falls back to the BIOS if that doesn't
1088 work. If unsure, go with the default, which is "Any".
1093 config PCI_GOMMCONFIG
1106 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1111 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1116 depends on PCI && (PCI_GOMMCONFIG || (PCI_GOANY && ACPI))
1120 source "drivers/pci/Kconfig"
1124 depends on !(X86_VOYAGER || X86_VISWS)
1126 Find out whether you have ISA slots on your motherboard. ISA is the
1127 name of a bus system, i.e. the way the CPU talks to the other stuff
1128 inside your box. Other bus systems are PCI, EISA, MicroChannel
1129 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1130 newer boards don't support it. If you have ISA, say Y, otherwise N.
1136 The Extended Industry Standard Architecture (EISA) bus was
1137 developed as an open alternative to the IBM MicroChannel bus.
1139 The EISA bus provided some of the features of the IBM MicroChannel
1140 bus while maintaining backward compatibility with cards made for
1141 the older ISA bus. The EISA bus saw limited use between 1988 and
1142 1995 when it was made obsolete by the PCI bus.
1144 Say Y here if you are building a kernel for an EISA-based machine.
1148 source "drivers/eisa/Kconfig"
1152 depends on !(X86_VISWS || X86_VOYAGER)
1154 MicroChannel Architecture is found in some IBM PS/2 machines and
1155 laptops. It is a bus system similar to PCI or ISA. See
1156 <file:Documentation/mca.txt> (and especially the web page given
1157 there) before attempting to build an MCA bus kernel.
1160 depends on X86_VOYAGER
1161 default y if X86_VOYAGER
1163 source "drivers/mca/Kconfig"
1166 tristate "NatSemi SCx200 support"
1167 depends on !X86_VOYAGER
1169 This provides basic support for the National Semiconductor SCx200
1170 processor. Right now this is just a driver for the GPIO pins.
1172 If you don't know what to do here, say N.
1174 This support is also available as a module. If compiled as a
1175 module, it will be called scx200.
1177 source "drivers/pcmcia/Kconfig"
1179 source "drivers/pci/hotplug/Kconfig"
1183 menu "Executable file formats"
1185 source "fs/Kconfig.binfmt"
1189 source "drivers/Kconfig"
1193 source "arch/i386/oprofile/Kconfig"
1195 source "arch/i386/Kconfig.debug"
1197 source "security/Kconfig"
1199 source "crypto/Kconfig"
1201 source "lib/Kconfig"
1204 # Use the generic interrupt handling code in kernel/irq/:
1206 config GENERIC_HARDIRQS
1210 config GENERIC_IRQ_PROBE
1216 depends on SMP && !X86_VOYAGER
1221 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1224 config X86_BIOS_REBOOT
1226 depends on !(X86_VISWS || X86_VOYAGER)
1229 config X86_TRAMPOLINE
1231 depends on X86_SMP || (X86_VOYAGER && SMP)
1236 depends on X86 && !EMBEDDED