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
557 int "Timer Frequency (100-20000)"
561 This allows you to specify the frequency at which the
562 kernel timer interrupt will occur.
566 depends on (MWINCHIP3D || MWINCHIP2 || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2) && !X86_NUMAQ
570 bool "Machine Check Exception"
571 depends on !X86_VOYAGER
573 Machine Check Exception support allows the processor to notify the
574 kernel if it detects a problem (e.g. overheating, component failure).
575 The action the kernel takes depends on the severity of the problem,
576 ranging from a warning message on the console, to halting the machine.
577 Your processor must be a Pentium or newer to support this - check the
578 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
579 have a design flaw which leads to false MCE events - hence MCE is
580 disabled on all P5 processors, unless explicitly enabled with "mce"
581 as a boot argument. Similarly, if MCE is built in and creates a
582 problem on some new non-standard machine, you can boot with "nomce"
583 to disable it. MCE support simply ignores non-MCE processors like
584 the 386 and 486, so nearly everyone can say Y here.
586 config X86_MCE_NONFATAL
587 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
590 Enabling this feature starts a timer that triggers every 5 seconds which
591 will look at the machine check registers to see if anything happened.
592 Non-fatal problems automatically get corrected (but still logged).
593 Disable this if you don't want to see these messages.
594 Seeing the messages this option prints out may be indicative of dying hardware,
595 or out-of-spec (ie, overclocked) hardware.
596 This option only does something on certain CPUs.
597 (AMD Athlon/Duron and Intel Pentium 4)
599 config X86_MCE_P4THERMAL
600 bool "check for P4 thermal throttling interrupt."
601 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
603 Enabling this feature will cause a message to be printed when the P4
604 enters thermal throttling.
607 tristate "Toshiba Laptop support"
609 This adds a driver to safely access the System Management Mode of
610 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
611 not work on models with a Phoenix BIOS. The System Management Mode
612 is used to set the BIOS and power saving options on Toshiba portables.
614 For information on utilities to make use of this driver see the
615 Toshiba Linux utilities web site at:
616 <http://www.buzzard.org.uk/toshiba/>.
618 Say Y if you intend to run this kernel on a Toshiba portable.
622 tristate "Dell laptop support"
624 This adds a driver to safely access the System Management Mode
625 of the CPU on the Dell Inspiron 8000. The System Management Mode
626 is used to read cpu temperature and cooling fan status and to
627 control the fans on the I8K portables.
629 This driver has been tested only on the Inspiron 8000 but it may
630 also work with other Dell laptops. You can force loading on other
631 models by passing the parameter `force=1' to the module. Use at
634 For information on utilities to make use of this driver see the
635 I8K Linux utilities web site at:
636 <http://people.debian.org/~dz/i8k/>
638 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
642 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
644 If you say Y here and also to "/dev file system support" in the
645 'File systems' section, you will be able to update the microcode on
646 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
647 Pentium III, Pentium 4, Xeon etc. You will obviously need the
648 actual microcode binary data itself which is not shipped with the
651 For latest news and information on obtaining all the required
652 ingredients for this driver, check:
653 <http://www.urbanmyth.org/microcode/>.
655 To compile this driver as a module, choose M here: the
656 module will be called microcode.
659 tristate "/dev/cpu/*/msr - Model-specific register support"
661 This device gives privileged processes access to the x86
662 Model-Specific Registers (MSRs). It is a character device with
663 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
664 MSR accesses are directed to a specific CPU on multi-processor
668 tristate "/dev/cpu/*/cpuid - CPU information support"
670 This device gives processes access to the x86 CPUID instruction to
671 be executed on a specific processor. It is a character device
672 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
675 source "drivers/firmware/Kconfig"
678 prompt "High Memory Support"
684 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
685 However, the address space of 32-bit x86 processors is only 4
686 Gigabytes large. That means that, if you have a large amount of
687 physical memory, not all of it can be "permanently mapped" by the
688 kernel. The physical memory that's not permanently mapped is called
691 If you are compiling a kernel which will never run on a machine with
692 more than 1 Gigabyte total physical RAM, answer "off" here (default
693 choice and suitable for most users). This will result in a "3GB/1GB"
694 split: 3GB are mapped so that each process sees a 3GB virtual memory
695 space and the remaining part of the 4GB virtual memory space is used
696 by the kernel to permanently map as much physical memory as
699 If the machine has between 1 and 4 Gigabytes physical RAM, then
702 If more than 4 Gigabytes is used then answer "64GB" here. This
703 selection turns Intel PAE (Physical Address Extension) mode on.
704 PAE implements 3-level paging on IA32 processors. PAE is fully
705 supported by Linux, PAE mode is implemented on all recent Intel
706 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
707 then the kernel will not boot on CPUs that don't support PAE!
709 The actual amount of total physical memory will either be
710 auto detected or can be forced by using a kernel command line option
711 such as "mem=256M". (Try "man bootparam" or see the documentation of
712 your boot loader (lilo or loadlin) about how to pass options to the
713 kernel at boot time.)
715 If unsure, say "off".
720 Select this if you have a 32-bit processor and between 1 and 4
721 gigabytes of physical RAM.
726 Select this if you have a 32-bit processor and more than 4
727 gigabytes of physical RAM.
732 prompt "Memory Split User Space"
735 A different Userspace/Kernel split allows you to
736 utilize up to alsmost 3GB of RAM without the requirement
737 for HIGHMEM. It also increases the available lowmem.
740 bool "3.0GB/1.0GB Kernel (Default)"
742 This is the default split of 3GB userspace to 1GB kernel
743 space, which will result in about 860MB of lowmem.
746 bool "2.5GB/1.5GB Kernel"
748 This split provides 2.5GB userspace and 1.5GB kernel
749 space, which will result in about 1370MB of lowmem.
752 bool "2.0GB/2.0GB Kernel"
754 This split provides 2GB userspace and 2GB kernel
755 space, which will result in about 1880MB of lowmem.
758 bool "1.5GB/2.5GB Kernel"
760 This split provides 1.5GB userspace and 2.5GB kernel
761 space, which will result in about 2390MB of lowmem.
764 bool "1.0GB/3.0GB Kernel"
766 This split provides 1GB userspace and 3GB kernel
767 space, which will result in about 2900MB of lowmem.
773 depends on HIGHMEM64G || HIGHMEM4G
778 depends on HIGHMEM64G
781 # Common NUMA Features
783 bool "Numa Memory Allocation and Scheduler Support"
784 depends on SMP && HIGHMEM64G && (X86_NUMAQ || X86_GENERICARCH || (X86_SUMMIT && ACPI))
786 default y if (X86_NUMAQ || X86_SUMMIT)
788 # Need comments to help the hapless user trying to turn on NUMA support
789 comment "NUMA (NUMA-Q) requires SMP, 64GB highmem support"
790 depends on X86_NUMAQ && (!HIGHMEM64G || !SMP)
792 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
793 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
800 config HAVE_ARCH_BOOTMEM_NODE
806 bool "Allocate 3rd-level pagetables from highmem"
807 depends on HIGHMEM4G || HIGHMEM64G
809 The VM uses one page table entry for each page of physical memory.
810 For systems with a lot of RAM, this can be wasteful of precious
811 low memory. Setting this option will put user-space page table
812 entries in high memory.
814 config MATH_EMULATION
815 bool "Math emulation"
817 Linux can emulate a math coprocessor (used for floating point
818 operations) if you don't have one. 486DX and Pentium processors have
819 a math coprocessor built in, 486SX and 386 do not, unless you added
820 a 487DX or 387, respectively. (The messages during boot time can
821 give you some hints here ["man dmesg"].) Everyone needs either a
822 coprocessor or this emulation.
824 If you don't have a math coprocessor, you need to say Y here; if you
825 say Y here even though you have a coprocessor, the coprocessor will
826 be used nevertheless. (This behavior can be changed with the kernel
827 command line option "no387", which comes handy if your coprocessor
828 is broken. Try "man bootparam" or see the documentation of your boot
829 loader (lilo or loadlin) about how to pass options to the kernel at
830 boot time.) This means that it is a good idea to say Y here if you
831 intend to use this kernel on different machines.
833 More information about the internals of the Linux math coprocessor
834 emulation can be found in <file:arch/i386/math-emu/README>.
836 If you are not sure, say Y; apart from resulting in a 66 KB bigger
837 kernel, it won't hurt.
840 bool "MTRR (Memory Type Range Register) support"
842 On Intel P6 family processors (Pentium Pro, Pentium II and later)
843 the Memory Type Range Registers (MTRRs) may be used to control
844 processor access to memory ranges. This is most useful if you have
845 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
846 allows bus write transfers to be combined into a larger transfer
847 before bursting over the PCI/AGP bus. This can increase performance
848 of image write operations 2.5 times or more. Saying Y here creates a
849 /proc/mtrr file which may be used to manipulate your processor's
850 MTRRs. Typically the X server should use this.
852 This code has a reasonably generic interface so that similar
853 control registers on other processors can be easily supported
856 The Cyrix 6x86, 6x86MX and M II processors have Address Range
857 Registers (ARRs) which provide a similar functionality to MTRRs. For
858 these, the ARRs are used to emulate the MTRRs.
859 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
860 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
861 write-combining. All of these processors are supported by this code
862 and it makes sense to say Y here if you have one of them.
864 Saying Y here also fixes a problem with buggy SMP BIOSes which only
865 set the MTRRs for the boot CPU and not for the secondary CPUs. This
866 can lead to all sorts of problems, so it's good to say Y here.
868 You can safely say Y even if your machine doesn't have MTRRs, you'll
869 just add about 9 KB to your kernel.
871 See <file:Documentation/mtrr.txt> for more information.
874 bool "Boot from EFI support (EXPERIMENTAL)"
879 This enables the the kernel to boot on EFI platforms using
880 system configuration information passed to it from the firmware.
881 This also enables the kernel to use any EFI runtime services that are
882 available (such as the EFI variable services).
884 This option is only useful on systems that have EFI firmware
885 and will result in a kernel image that is ~8k larger. In addition,
886 you must use the latest ELILO loader available at
887 <http://elilo.sourceforge.net> in order to take advantage of
888 kernel initialization using EFI information (neither GRUB nor LILO know
889 anything about EFI). However, even with this option, the resultant
890 kernel should continue to boot on existing non-EFI platforms.
893 bool "Enable kernel irq balancing"
894 depends on SMP && X86_IO_APIC
897 The default yes will allow the kernel to do irq load balancing.
898 Saying no will keep the kernel from doing irq load balancing.
902 depends on (SMP || PREEMPT) && X86_CMPXCHG
905 # turning this on wastes a bunch of space.
906 # Summit needs it only when NUMA is on
909 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
913 bool "Use register arguments (EXPERIMENTAL)"
914 depends on EXPERIMENTAL
917 Compile the kernel with -mregparm=3. This uses an different ABI
918 and passes the first three arguments of a function call in registers.
919 This will probably break binary only modules.
921 This feature is only enabled for gcc-3.0 and later - earlier compilers
922 generate incorrect output with certain kernel constructs when
928 menu "Power management options (ACPI, APM)"
929 depends on !X86_VOYAGER
931 source kernel/power/Kconfig
933 source "drivers/acpi/Kconfig"
935 menu "APM (Advanced Power Management) BIOS Support"
936 depends on PM && !X86_VISWS
939 tristate "APM (Advanced Power Management) BIOS support"
942 APM is a BIOS specification for saving power using several different
943 techniques. This is mostly useful for battery powered laptops with
944 APM compliant BIOSes. If you say Y here, the system time will be
945 reset after a RESUME operation, the /proc/apm device will provide
946 battery status information, and user-space programs will receive
947 notification of APM "events" (e.g. battery status change).
949 If you select "Y" here, you can disable actual use of the APM
950 BIOS by passing the "apm=off" option to the kernel at boot time.
952 Note that the APM support is almost completely disabled for
953 machines with more than one CPU.
955 In order to use APM, you will need supporting software. For location
956 and more information, read <file:Documentation/pm.txt> and the
957 Battery Powered Linux mini-HOWTO, available from
958 <http://www.tldp.org/docs.html#howto>.
960 This driver does not spin down disk drives (see the hdparm(8)
961 manpage ("man 8 hdparm") for that), and it doesn't turn off
962 VESA-compliant "green" monitors.
964 This driver does not support the TI 4000M TravelMate and the ACER
965 486/DX4/75 because they don't have compliant BIOSes. Many "green"
966 desktop machines also don't have compliant BIOSes, and this driver
967 may cause those machines to panic during the boot phase.
969 Generally, if you don't have a battery in your machine, there isn't
970 much point in using this driver and you should say N. If you get
971 random kernel OOPSes or reboots that don't seem to be related to
972 anything, try disabling/enabling this option (or disabling/enabling
975 Some other things you should try when experiencing seemingly random,
978 1) make sure that you have enough swap space and that it is
980 2) pass the "no-hlt" option to the kernel
981 3) switch on floating point emulation in the kernel and pass
982 the "no387" option to the kernel
983 4) pass the "floppy=nodma" option to the kernel
984 5) pass the "mem=4M" option to the kernel (thereby disabling
985 all but the first 4 MB of RAM)
986 6) make sure that the CPU is not over clocked.
987 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
988 8) disable the cache from your BIOS settings
989 9) install a fan for the video card or exchange video RAM
990 10) install a better fan for the CPU
991 11) exchange RAM chips
992 12) exchange the motherboard.
994 To compile this driver as a module, choose M here: the
995 module will be called apm.
997 config APM_IGNORE_USER_SUSPEND
998 bool "Ignore USER SUSPEND"
1001 This option will ignore USER SUSPEND requests. On machines with a
1002 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1003 series notebooks, it is necessary to say Y because of a BIOS bug.
1005 config APM_DO_ENABLE
1006 bool "Enable PM at boot time"
1009 Enable APM features at boot time. From page 36 of the APM BIOS
1010 specification: "When disabled, the APM BIOS does not automatically
1011 power manage devices, enter the Standby State, enter the Suspend
1012 State, or take power saving steps in response to CPU Idle calls."
1013 This driver will make CPU Idle calls when Linux is idle (unless this
1014 feature is turned off -- see "Do CPU IDLE calls", below). This
1015 should always save battery power, but more complicated APM features
1016 will be dependent on your BIOS implementation. You may need to turn
1017 this option off if your computer hangs at boot time when using APM
1018 support, or if it beeps continuously instead of suspending. Turn
1019 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1020 T400CDT. This is off by default since most machines do fine without
1024 bool "Make CPU Idle calls when idle"
1027 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1028 On some machines, this can activate improved power savings, such as
1029 a slowed CPU clock rate, when the machine is idle. These idle calls
1030 are made after the idle loop has run for some length of time (e.g.,
1031 333 mS). On some machines, this will cause a hang at boot time or
1032 whenever the CPU becomes idle. (On machines with more than one CPU,
1033 this option does nothing.)
1035 config APM_DISPLAY_BLANK
1036 bool "Enable console blanking using APM"
1039 Enable console blanking using the APM. Some laptops can use this to
1040 turn off the LCD backlight when the screen blanker of the Linux
1041 virtual console blanks the screen. Note that this is only used by
1042 the virtual console screen blanker, and won't turn off the backlight
1043 when using the X Window system. This also doesn't have anything to
1044 do with your VESA-compliant power-saving monitor. Further, this
1045 option doesn't work for all laptops -- it might not turn off your
1046 backlight at all, or it might print a lot of errors to the console,
1047 especially if you are using gpm.
1049 config APM_RTC_IS_GMT
1050 bool "RTC stores time in GMT"
1053 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
1054 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
1057 It is in fact recommended to store GMT in your RTC, because then you
1058 don't have to worry about daylight savings time changes. The only
1059 reason not to use GMT in your RTC is if you also run a broken OS
1060 that doesn't understand GMT.
1062 config APM_ALLOW_INTS
1063 bool "Allow interrupts during APM BIOS calls"
1066 Normally we disable external interrupts while we are making calls to
1067 the APM BIOS as a measure to lessen the effects of a badly behaving
1068 BIOS implementation. The BIOS should reenable interrupts if it
1069 needs to. Unfortunately, some BIOSes do not -- especially those in
1070 many of the newer IBM Thinkpads. If you experience hangs when you
1071 suspend, try setting this to Y. Otherwise, say N.
1073 config APM_REAL_MODE_POWER_OFF
1074 bool "Use real mode APM BIOS call to power off"
1077 Use real mode APM BIOS calls to switch off the computer. This is
1078 a work-around for a number of buggy BIOSes. Switch this option on if
1079 your computer crashes instead of powering off properly.
1083 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1087 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1089 config X86_VISWS_APIC
1091 depends on X86_VISWS
1094 config X86_LOCAL_APIC
1096 depends on (X86_VISWS || SMP) && !X86_VOYAGER
1101 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1105 bool "PCI support" if !X86_VISWS
1106 depends on !X86_VOYAGER
1107 default y if X86_VISWS
1109 Find out whether you have a PCI motherboard. PCI is the name of a
1110 bus system, i.e. the way the CPU talks to the other stuff inside
1111 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1112 VESA. If you have PCI, say Y, otherwise N.
1114 The PCI-HOWTO, available from
1115 <http://www.tldp.org/docs.html#howto>, contains valuable
1116 information about which PCI hardware does work under Linux and which
1120 prompt "PCI access mode"
1121 depends on PCI && !X86_VISWS
1124 On PCI systems, the BIOS can be used to detect the PCI devices and
1125 determine their configuration. However, some old PCI motherboards
1126 have BIOS bugs and may crash if this is done. Also, some embedded
1127 PCI-based systems don't have any BIOS at all. Linux can also try to
1128 detect the PCI hardware directly without using the BIOS.
1130 With this option, you can specify how Linux should detect the
1131 PCI devices. If you choose "BIOS", the BIOS will be used,
1132 if you choose "Direct", the BIOS won't be used, and if you
1133 choose "MMConfig", then PCI Express MMCONFIG will be used.
1134 If you choose "Any", the kernel will try MMCONFIG, then the
1135 direct access method and falls back to the BIOS if that doesn't
1136 work. If unsure, go with the default, which is "Any".
1141 config PCI_GOMMCONFIG
1154 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1159 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1164 depends on PCI && (PCI_GOMMCONFIG || (PCI_GOANY && ACPI))
1168 source "drivers/pci/Kconfig"
1172 depends on !(X86_VOYAGER || X86_VISWS)
1174 Find out whether you have ISA slots on your motherboard. ISA is the
1175 name of a bus system, i.e. the way the CPU talks to the other stuff
1176 inside your box. Other bus systems are PCI, EISA, MicroChannel
1177 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1178 newer boards don't support it. If you have ISA, say Y, otherwise N.
1184 The Extended Industry Standard Architecture (EISA) bus was
1185 developed as an open alternative to the IBM MicroChannel bus.
1187 The EISA bus provided some of the features of the IBM MicroChannel
1188 bus while maintaining backward compatibility with cards made for
1189 the older ISA bus. The EISA bus saw limited use between 1988 and
1190 1995 when it was made obsolete by the PCI bus.
1192 Say Y here if you are building a kernel for an EISA-based machine.
1196 source "drivers/eisa/Kconfig"
1200 depends on !(X86_VISWS || X86_VOYAGER)
1202 MicroChannel Architecture is found in some IBM PS/2 machines and
1203 laptops. It is a bus system similar to PCI or ISA. See
1204 <file:Documentation/mca.txt> (and especially the web page given
1205 there) before attempting to build an MCA bus kernel.
1208 depends on X86_VOYAGER
1209 default y if X86_VOYAGER
1211 source "drivers/mca/Kconfig"
1214 tristate "NatSemi SCx200 support"
1215 depends on !X86_VOYAGER
1217 This provides basic support for the National Semiconductor SCx200
1218 processor. Right now this is just a driver for the GPIO pins.
1220 If you don't know what to do here, say N.
1222 This support is also available as a module. If compiled as a
1223 module, it will be called scx200.
1225 source "drivers/pcmcia/Kconfig"
1227 source "drivers/pci/hotplug/Kconfig"
1231 menu "Executable file formats"
1233 source "fs/Kconfig.binfmt"
1237 source "drivers/Kconfig"
1241 source "arch/i386/oprofile/Kconfig"
1243 source "arch/i386/Kconfig.debug"
1245 source "kernel/vserver/Kconfig"
1247 source "security/Kconfig"
1249 source "crypto/Kconfig"
1251 source "lib/Kconfig"
1254 # Use the generic interrupt handling code in kernel/irq/:
1256 config GENERIC_HARDIRQS
1260 config GENERIC_IRQ_PROBE
1266 depends on SMP && !X86_VOYAGER
1271 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1274 config X86_BIOS_REBOOT
1276 depends on !(X86_VISWS || X86_VOYAGER)
1279 config X86_TRAMPOLINE
1281 depends on X86_SMP || (X86_VOYAGER && SMP)
1286 depends on X86 && !EMBEDDED