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 GENERIC_CALIBRATE_DELAY
380 config X86_PPRO_FENCE
382 depends on M686 || M586MMX || M586TSC || M586 || M486 || M386
387 depends on M586MMX || M586TSC || M586 || M486 || M386
390 config X86_WP_WORKS_OK
410 config X86_ALIGNMENT_16
412 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || X86_ELAN || MK6 || M586MMX || M586TSC || M586 || M486 || MVIAC3_2
417 depends on MK7 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || MK8 || MEFFICEON
420 config X86_INTEL_USERCOPY
422 depends on MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M586MMX || X86_GENERIC || MK8 || MK7 || MEFFICEON
425 config X86_USE_PPRO_CHECKSUM
427 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC3_2 || MEFFICEON
432 depends on MCYRIXIII || MK7
437 depends on (MWINCHIP3D || MWINCHIP2 || MWINCHIPC6) && MTRR
441 bool "HPET Timer Support"
443 This enables the use of the HPET for the kernel's internal timer.
444 HPET is the next generation timer replacing legacy 8254s.
445 You can safely choose Y here. However, HPET will only be
446 activated if the platform and the BIOS support this feature.
447 Otherwise the 8254 will be used for timing services.
449 Choose N to continue using the legacy 8254 timer.
451 config HPET_EMULATE_RTC
452 bool "Provide RTC interrupt"
453 depends on HPET_TIMER && RTC=y
456 bool "Symmetric multi-processing support"
458 This enables support for systems with more than one CPU. If you have
459 a system with only one CPU, like most personal computers, say N. If
460 you have a system with more than one CPU, say Y.
462 If you say N here, the kernel will run on single and multiprocessor
463 machines, but will use only one CPU of a multiprocessor machine. If
464 you say Y here, the kernel will run on many, but not all,
465 singleprocessor machines. On a singleprocessor machine, the kernel
466 will run faster if you say N here.
468 Note that if you say Y here and choose architecture "586" or
469 "Pentium" under "Processor family", the kernel will not work on 486
470 architectures. Similarly, multiprocessor kernels for the "PPro"
471 architecture may not work on all Pentium based boards.
473 People using multiprocessor machines who say Y here should also say
474 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
475 Management" code will be disabled if you say Y here.
477 See also the <file:Documentation/smp.txt>,
478 <file:Documentation/i386/IO-APIC.txt>,
479 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
480 <http://www.tldp.org/docs.html#howto>.
482 If you don't know what to do here, say N.
485 int "Maximum number of CPUs (2-255)"
488 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
491 This allows you to specify the maximum number of CPUs which this
492 kernel will support. The maximum supported value is 255 and the
493 minimum value which makes sense is 2.
495 This is purely to save memory - each supported CPU adds
496 approximately eight kilobytes to the kernel image.
499 bool "SMT (Hyperthreading) scheduler support"
503 SMT scheduler support improves the CPU scheduler's decision making
504 when dealing with Intel Pentium 4 chips with HyperThreading at a
505 cost of slightly increased overhead in some places. If unsure say
509 bool "Preemptible Kernel"
511 This option reduces the latency of the kernel when reacting to
512 real-time or interactive events by allowing a low priority process to
513 be preempted even if it is in kernel mode executing a system call.
514 This allows applications to run more reliably even when the system is
517 Say Y here if you are building a kernel for a desktop, embedded
518 or real-time system. Say N if you are unsure.
521 bool "Preempt The Big Kernel Lock"
525 This option reduces the latency of the kernel by making the
526 big kernel lock preemptible.
528 Say Y here if you are building a kernel for a desktop system.
529 Say N if you are unsure.
532 bool "Local APIC support on uniprocessors" if !SMP
533 depends on !(X86_VISWS || X86_VOYAGER)
535 A local APIC (Advanced Programmable Interrupt Controller) is an
536 integrated interrupt controller in the CPU. If you have a single-CPU
537 system which has a processor with a local APIC, you can say Y here to
538 enable and use it. If you say Y here even though your machine doesn't
539 have a local APIC, then the kernel will still run with no slowdown at
540 all. The local APIC supports CPU-generated self-interrupts (timer,
541 performance counters), and the NMI watchdog which detects hard
544 If you have a system with several CPUs, you do not need to say Y
545 here: the local APIC will be used automatically.
548 bool "IO-APIC support on uniprocessors"
549 depends on !SMP && X86_UP_APIC
551 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
552 SMP-capable replacement for PC-style interrupt controllers. Most
553 SMP systems and a small number of uniprocessor systems have one.
554 If you have a single-CPU system with an IO-APIC, you can say Y here
555 to use it. If you say Y here even though your machine doesn't have
556 an IO-APIC, then the kernel will still run with no slowdown at all.
558 If you have a system with several CPUs, you do not need to say Y
559 here: the IO-APIC will be used automatically.
561 config X86_LOCAL_APIC
563 depends on !SMP && X86_UP_APIC
568 depends on !SMP && X86_UP_IOAPIC
572 int "Timer Frequency (100-10000)"
576 This allows you to specify the frequency at which the
577 kernel timer interrupt will occur.
581 depends on (MWINCHIP3D || MWINCHIP2 || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2) && !X86_NUMAQ
585 bool "Machine Check Exception"
586 depends on !X86_VOYAGER
588 Machine Check Exception support allows the processor to notify the
589 kernel if it detects a problem (e.g. overheating, component failure).
590 The action the kernel takes depends on the severity of the problem,
591 ranging from a warning message on the console, to halting the machine.
592 Your processor must be a Pentium or newer to support this - check the
593 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
594 have a design flaw which leads to false MCE events - hence MCE is
595 disabled on all P5 processors, unless explicitly enabled with "mce"
596 as a boot argument. Similarly, if MCE is built in and creates a
597 problem on some new non-standard machine, you can boot with "nomce"
598 to disable it. MCE support simply ignores non-MCE processors like
599 the 386 and 486, so nearly everyone can say Y here.
601 config X86_MCE_NONFATAL
602 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
605 Enabling this feature starts a timer that triggers every 5 seconds which
606 will look at the machine check registers to see if anything happened.
607 Non-fatal problems automatically get corrected (but still logged).
608 Disable this if you don't want to see these messages.
609 Seeing the messages this option prints out may be indicative of dying hardware,
610 or out-of-spec (ie, overclocked) hardware.
611 This option only does something on certain CPUs.
612 (AMD Athlon/Duron and Intel Pentium 4)
614 config X86_MCE_P4THERMAL
615 bool "check for P4 thermal throttling interrupt."
616 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
618 Enabling this feature will cause a message to be printed when the P4
619 enters thermal throttling.
622 tristate "Toshiba Laptop support"
624 This adds a driver to safely access the System Management Mode of
625 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
626 not work on models with a Phoenix BIOS. The System Management Mode
627 is used to set the BIOS and power saving options on Toshiba portables.
629 For information on utilities to make use of this driver see the
630 Toshiba Linux utilities web site at:
631 <http://www.buzzard.org.uk/toshiba/>.
633 Say Y if you intend to run this kernel on a Toshiba portable.
637 tristate "Dell laptop support"
639 This adds a driver to safely access the System Management Mode
640 of the CPU on the Dell Inspiron 8000. The System Management Mode
641 is used to read cpu temperature and cooling fan status and to
642 control the fans on the I8K portables.
644 This driver has been tested only on the Inspiron 8000 but it may
645 also work with other Dell laptops. You can force loading on other
646 models by passing the parameter `force=1' to the module. Use at
649 For information on utilities to make use of this driver see the
650 I8K Linux utilities web site at:
651 <http://people.debian.org/~dz/i8k/>
653 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
657 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
659 If you say Y here and also to "/dev file system support" in the
660 'File systems' section, you will be able to update the microcode on
661 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
662 Pentium III, Pentium 4, Xeon etc. You will obviously need the
663 actual microcode binary data itself which is not shipped with the
666 For latest news and information on obtaining all the required
667 ingredients for this driver, check:
668 <http://www.urbanmyth.org/microcode/>.
670 To compile this driver as a module, choose M here: the
671 module will be called microcode.
674 tristate "/dev/cpu/*/msr - Model-specific register support"
676 This device gives privileged processes access to the x86
677 Model-Specific Registers (MSRs). It is a character device with
678 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
679 MSR accesses are directed to a specific CPU on multi-processor
683 tristate "/dev/cpu/*/cpuid - CPU information support"
685 This device gives processes access to the x86 CPUID instruction to
686 be executed on a specific processor. It is a character device
687 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
690 source "drivers/firmware/Kconfig"
693 prompt "High Memory Support"
699 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
700 However, the address space of 32-bit x86 processors is only 4
701 Gigabytes large. That means that, if you have a large amount of
702 physical memory, not all of it can be "permanently mapped" by the
703 kernel. The physical memory that's not permanently mapped is called
706 If you are compiling a kernel which will never run on a machine with
707 more than 1 Gigabyte total physical RAM, answer "off" here (default
708 choice and suitable for most users). This will result in a "3GB/1GB"
709 split: 3GB are mapped so that each process sees a 3GB virtual memory
710 space and the remaining part of the 4GB virtual memory space is used
711 by the kernel to permanently map as much physical memory as
714 If the machine has between 1 and 4 Gigabytes physical RAM, then
717 If more than 4 Gigabytes is used then answer "64GB" here. This
718 selection turns Intel PAE (Physical Address Extension) mode on.
719 PAE implements 3-level paging on IA32 processors. PAE is fully
720 supported by Linux, PAE mode is implemented on all recent Intel
721 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
722 then the kernel will not boot on CPUs that don't support PAE!
724 The actual amount of total physical memory will either be
725 auto detected or can be forced by using a kernel command line option
726 such as "mem=256M". (Try "man bootparam" or see the documentation of
727 your boot loader (lilo or loadlin) about how to pass options to the
728 kernel at boot time.)
730 If unsure, say "off".
735 Select this if you have a 32-bit processor and between 1 and 4
736 gigabytes of physical RAM.
741 Select this if you have a 32-bit processor and more than 4
742 gigabytes of physical RAM.
747 prompt "Memory Split User Space"
750 A different Userspace/Kernel split allows you to
751 utilize up to alsmost 3GB of RAM without the requirement
752 for HIGHMEM. It also increases the available lowmem.
755 bool "3.0GB/1.0GB Kernel (Default)"
757 This is the default split of 3GB userspace to 1GB kernel
758 space, which will result in about 860MB of lowmem.
761 bool "2.5GB/1.5GB Kernel"
763 This split provides 2.5GB userspace and 1.5GB kernel
764 space, which will result in about 1370MB of lowmem.
767 bool "2.0GB/2.0GB Kernel"
769 This split provides 2GB userspace and 2GB kernel
770 space, which will result in about 1880MB of lowmem.
773 bool "1.5GB/2.5GB Kernel"
775 This split provides 1.5GB userspace and 2.5GB kernel
776 space, which will result in about 2390MB of lowmem.
779 bool "1.0GB/3.0GB Kernel"
781 This split provides 1GB userspace and 3GB kernel
782 space, which will result in about 2900MB of lowmem.
788 depends on HIGHMEM64G || HIGHMEM4G
793 depends on HIGHMEM64G
796 # Common NUMA Features
798 bool "Numa Memory Allocation and Scheduler Support"
799 depends on SMP && HIGHMEM64G && (X86_NUMAQ || X86_GENERICARCH || (X86_SUMMIT && ACPI))
801 default y if (X86_NUMAQ || X86_SUMMIT)
803 # Need comments to help the hapless user trying to turn on NUMA support
804 comment "NUMA (NUMA-Q) requires SMP, 64GB highmem support"
805 depends on X86_NUMAQ && (!HIGHMEM64G || !SMP)
807 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
808 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
815 config HAVE_ARCH_BOOTMEM_NODE
821 bool "Allocate 3rd-level pagetables from highmem"
822 depends on HIGHMEM4G || HIGHMEM64G
824 The VM uses one page table entry for each page of physical memory.
825 For systems with a lot of RAM, this can be wasteful of precious
826 low memory. Setting this option will put user-space page table
827 entries in high memory.
829 config MATH_EMULATION
830 bool "Math emulation"
832 Linux can emulate a math coprocessor (used for floating point
833 operations) if you don't have one. 486DX and Pentium processors have
834 a math coprocessor built in, 486SX and 386 do not, unless you added
835 a 487DX or 387, respectively. (The messages during boot time can
836 give you some hints here ["man dmesg"].) Everyone needs either a
837 coprocessor or this emulation.
839 If you don't have a math coprocessor, you need to say Y here; if you
840 say Y here even though you have a coprocessor, the coprocessor will
841 be used nevertheless. (This behavior can be changed with the kernel
842 command line option "no387", which comes handy if your coprocessor
843 is broken. Try "man bootparam" or see the documentation of your boot
844 loader (lilo or loadlin) about how to pass options to the kernel at
845 boot time.) This means that it is a good idea to say Y here if you
846 intend to use this kernel on different machines.
848 More information about the internals of the Linux math coprocessor
849 emulation can be found in <file:arch/i386/math-emu/README>.
851 If you are not sure, say Y; apart from resulting in a 66 KB bigger
852 kernel, it won't hurt.
855 bool "MTRR (Memory Type Range Register) support"
857 On Intel P6 family processors (Pentium Pro, Pentium II and later)
858 the Memory Type Range Registers (MTRRs) may be used to control
859 processor access to memory ranges. This is most useful if you have
860 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
861 allows bus write transfers to be combined into a larger transfer
862 before bursting over the PCI/AGP bus. This can increase performance
863 of image write operations 2.5 times or more. Saying Y here creates a
864 /proc/mtrr file which may be used to manipulate your processor's
865 MTRRs. Typically the X server should use this.
867 This code has a reasonably generic interface so that similar
868 control registers on other processors can be easily supported
871 The Cyrix 6x86, 6x86MX and M II processors have Address Range
872 Registers (ARRs) which provide a similar functionality to MTRRs. For
873 these, the ARRs are used to emulate the MTRRs.
874 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
875 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
876 write-combining. All of these processors are supported by this code
877 and it makes sense to say Y here if you have one of them.
879 Saying Y here also fixes a problem with buggy SMP BIOSes which only
880 set the MTRRs for the boot CPU and not for the secondary CPUs. This
881 can lead to all sorts of problems, so it's good to say Y here.
883 You can safely say Y even if your machine doesn't have MTRRs, you'll
884 just add about 9 KB to your kernel.
886 See <file:Documentation/mtrr.txt> for more information.
889 bool "Boot from EFI support (EXPERIMENTAL)"
893 This enables the the kernel to boot on EFI platforms using
894 system configuration information passed to it from the firmware.
895 This also enables the kernel to use any EFI runtime services that are
896 available (such as the EFI variable services).
898 This option is only useful on systems that have EFI firmware
899 and will result in a kernel image that is ~8k larger. In addition,
900 you must use the latest ELILO loader available at
901 <http://elilo.sourceforge.net> in order to take advantage of
902 kernel initialization using EFI information (neither GRUB nor LILO know
903 anything about EFI). However, even with this option, the resultant
904 kernel should continue to boot on existing non-EFI platforms.
907 bool "Enable kernel irq balancing"
908 depends on SMP && X86_IO_APIC
911 The default yes will allow the kernel to do irq load balancing.
912 Saying no will keep the kernel from doing irq load balancing.
916 depends on (SMP || PREEMPT) && X86_CMPXCHG
919 # turning this on wastes a bunch of space.
920 # Summit needs it only when NUMA is on
923 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
927 bool "Use register arguments (EXPERIMENTAL)"
928 depends on EXPERIMENTAL
931 Compile the kernel with -mregparm=3. This uses a different ABI
932 and passes the first three arguments of a function call in registers.
933 This will probably break binary only modules.
935 This feature is only enabled for gcc-3.0 and later - earlier compilers
936 generate incorrect output with certain kernel constructs when
942 menu "Power management options (ACPI, APM)"
943 depends on !X86_VOYAGER
945 source kernel/power/Kconfig
947 source "drivers/acpi/Kconfig"
949 menu "APM (Advanced Power Management) BIOS Support"
950 depends on PM && !X86_VISWS
953 tristate "APM (Advanced Power Management) BIOS support"
956 APM is a BIOS specification for saving power using several different
957 techniques. This is mostly useful for battery powered laptops with
958 APM compliant BIOSes. If you say Y here, the system time will be
959 reset after a RESUME operation, the /proc/apm device will provide
960 battery status information, and user-space programs will receive
961 notification of APM "events" (e.g. battery status change).
963 If you select "Y" here, you can disable actual use of the APM
964 BIOS by passing the "apm=off" option to the kernel at boot time.
966 Note that the APM support is almost completely disabled for
967 machines with more than one CPU.
969 In order to use APM, you will need supporting software. For location
970 and more information, read <file:Documentation/pm.txt> and the
971 Battery Powered Linux mini-HOWTO, available from
972 <http://www.tldp.org/docs.html#howto>.
974 This driver does not spin down disk drives (see the hdparm(8)
975 manpage ("man 8 hdparm") for that), and it doesn't turn off
976 VESA-compliant "green" monitors.
978 This driver does not support the TI 4000M TravelMate and the ACER
979 486/DX4/75 because they don't have compliant BIOSes. Many "green"
980 desktop machines also don't have compliant BIOSes, and this driver
981 may cause those machines to panic during the boot phase.
983 Generally, if you don't have a battery in your machine, there isn't
984 much point in using this driver and you should say N. If you get
985 random kernel OOPSes or reboots that don't seem to be related to
986 anything, try disabling/enabling this option (or disabling/enabling
989 Some other things you should try when experiencing seemingly random,
992 1) make sure that you have enough swap space and that it is
994 2) pass the "no-hlt" option to the kernel
995 3) switch on floating point emulation in the kernel and pass
996 the "no387" option to the kernel
997 4) pass the "floppy=nodma" option to the kernel
998 5) pass the "mem=4M" option to the kernel (thereby disabling
999 all but the first 4 MB of RAM)
1000 6) make sure that the CPU is not over clocked.
1001 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1002 8) disable the cache from your BIOS settings
1003 9) install a fan for the video card or exchange video RAM
1004 10) install a better fan for the CPU
1005 11) exchange RAM chips
1006 12) exchange the motherboard.
1008 To compile this driver as a module, choose M here: the
1009 module will be called apm.
1011 config APM_IGNORE_USER_SUSPEND
1012 bool "Ignore USER SUSPEND"
1015 This option will ignore USER SUSPEND requests. On machines with a
1016 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1017 series notebooks, it is necessary to say Y because of a BIOS bug.
1019 config APM_DO_ENABLE
1020 bool "Enable PM at boot time"
1023 Enable APM features at boot time. From page 36 of the APM BIOS
1024 specification: "When disabled, the APM BIOS does not automatically
1025 power manage devices, enter the Standby State, enter the Suspend
1026 State, or take power saving steps in response to CPU Idle calls."
1027 This driver will make CPU Idle calls when Linux is idle (unless this
1028 feature is turned off -- see "Do CPU IDLE calls", below). This
1029 should always save battery power, but more complicated APM features
1030 will be dependent on your BIOS implementation. You may need to turn
1031 this option off if your computer hangs at boot time when using APM
1032 support, or if it beeps continuously instead of suspending. Turn
1033 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1034 T400CDT. This is off by default since most machines do fine without
1038 bool "Make CPU Idle calls when idle"
1041 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1042 On some machines, this can activate improved power savings, such as
1043 a slowed CPU clock rate, when the machine is idle. These idle calls
1044 are made after the idle loop has run for some length of time (e.g.,
1045 333 mS). On some machines, this will cause a hang at boot time or
1046 whenever the CPU becomes idle. (On machines with more than one CPU,
1047 this option does nothing.)
1049 config APM_DISPLAY_BLANK
1050 bool "Enable console blanking using APM"
1053 Enable console blanking using the APM. Some laptops can use this to
1054 turn off the LCD backlight when the screen blanker of the Linux
1055 virtual console blanks the screen. Note that this is only used by
1056 the virtual console screen blanker, and won't turn off the backlight
1057 when using the X Window system. This also doesn't have anything to
1058 do with your VESA-compliant power-saving monitor. Further, this
1059 option doesn't work for all laptops -- it might not turn off your
1060 backlight at all, or it might print a lot of errors to the console,
1061 especially if you are using gpm.
1063 config APM_RTC_IS_GMT
1064 bool "RTC stores time in GMT"
1067 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
1068 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
1071 It is in fact recommended to store GMT in your RTC, because then you
1072 don't have to worry about daylight savings time changes. The only
1073 reason not to use GMT in your RTC is if you also run a broken OS
1074 that doesn't understand GMT.
1076 config APM_ALLOW_INTS
1077 bool "Allow interrupts during APM BIOS calls"
1080 Normally we disable external interrupts while we are making calls to
1081 the APM BIOS as a measure to lessen the effects of a badly behaving
1082 BIOS implementation. The BIOS should reenable interrupts if it
1083 needs to. Unfortunately, some BIOSes do not -- especially those in
1084 many of the newer IBM Thinkpads. If you experience hangs when you
1085 suspend, try setting this to Y. Otherwise, say N.
1087 config APM_REAL_MODE_POWER_OFF
1088 bool "Use real mode APM BIOS call to power off"
1091 Use real mode APM BIOS calls to switch off the computer. This is
1092 a work-around for a number of buggy BIOSes. Switch this option on if
1093 your computer crashes instead of powering off properly.
1097 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1101 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1103 config X86_VISWS_APIC
1105 depends on X86_VISWS
1108 config X86_LOCAL_APIC
1110 depends on (X86_VISWS || SMP) && !X86_VOYAGER
1115 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1119 bool "PCI support" if !X86_VISWS
1120 depends on !X86_VOYAGER
1121 default y if X86_VISWS
1123 Find out whether you have a PCI motherboard. PCI is the name of a
1124 bus system, i.e. the way the CPU talks to the other stuff inside
1125 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1126 VESA. If you have PCI, say Y, otherwise N.
1128 The PCI-HOWTO, available from
1129 <http://www.tldp.org/docs.html#howto>, contains valuable
1130 information about which PCI hardware does work under Linux and which
1134 prompt "PCI access mode"
1135 depends on PCI && !X86_VISWS
1138 On PCI systems, the BIOS can be used to detect the PCI devices and
1139 determine their configuration. However, some old PCI motherboards
1140 have BIOS bugs and may crash if this is done. Also, some embedded
1141 PCI-based systems don't have any BIOS at all. Linux can also try to
1142 detect the PCI hardware directly without using the BIOS.
1144 With this option, you can specify how Linux should detect the
1145 PCI devices. If you choose "BIOS", the BIOS will be used,
1146 if you choose "Direct", the BIOS won't be used, and if you
1147 choose "MMConfig", then PCI Express MMCONFIG will be used.
1148 If you choose "Any", the kernel will try MMCONFIG, then the
1149 direct access method and falls back to the BIOS if that doesn't
1150 work. If unsure, go with the default, which is "Any".
1155 config PCI_GOMMCONFIG
1168 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1173 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1178 depends on PCI && (PCI_GOMMCONFIG || (PCI_GOANY && ACPI))
1182 source "drivers/pci/pcie/Kconfig"
1184 source "drivers/pci/Kconfig"
1188 depends on !(X86_VOYAGER || X86_VISWS)
1190 Find out whether you have ISA slots on your motherboard. ISA is the
1191 name of a bus system, i.e. the way the CPU talks to the other stuff
1192 inside your box. Other bus systems are PCI, EISA, MicroChannel
1193 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1194 newer boards don't support it. If you have ISA, say Y, otherwise N.
1200 The Extended Industry Standard Architecture (EISA) bus was
1201 developed as an open alternative to the IBM MicroChannel bus.
1203 The EISA bus provided some of the features of the IBM MicroChannel
1204 bus while maintaining backward compatibility with cards made for
1205 the older ISA bus. The EISA bus saw limited use between 1988 and
1206 1995 when it was made obsolete by the PCI bus.
1208 Say Y here if you are building a kernel for an EISA-based machine.
1212 source "drivers/eisa/Kconfig"
1216 depends on !(X86_VISWS || X86_VOYAGER)
1218 MicroChannel Architecture is found in some IBM PS/2 machines and
1219 laptops. It is a bus system similar to PCI or ISA. See
1220 <file:Documentation/mca.txt> (and especially the web page given
1221 there) before attempting to build an MCA bus kernel.
1224 depends on X86_VOYAGER
1225 default y if X86_VOYAGER
1227 source "drivers/mca/Kconfig"
1230 tristate "NatSemi SCx200 support"
1231 depends on !X86_VOYAGER
1233 This provides basic support for the National Semiconductor SCx200
1234 processor. Right now this is just a driver for the GPIO pins.
1236 If you don't know what to do here, say N.
1238 This support is also available as a module. If compiled as a
1239 module, it will be called scx200.
1241 source "drivers/pcmcia/Kconfig"
1243 source "drivers/pci/hotplug/Kconfig"
1247 menu "Executable file formats"
1249 source "fs/Kconfig.binfmt"
1253 source "drivers/Kconfig"
1257 source "arch/i386/oprofile/Kconfig"
1259 source "arch/i386/Kconfig.debug"
1261 source "kernel/vserver/Kconfig"
1263 source "security/Kconfig"
1265 source "crypto/Kconfig"
1267 source "lib/Kconfig"
1270 # Use the generic interrupt handling code in kernel/irq/:
1272 config GENERIC_HARDIRQS
1276 config GENERIC_IRQ_PROBE
1282 depends on SMP && !X86_VOYAGER
1287 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1290 config X86_BIOS_REBOOT
1292 depends on !(X86_VISWS || X86_VOYAGER)
1295 config X86_TRAMPOLINE
1297 depends on X86_SMP || (X86_VOYAGER && SMP)
1302 depends on X86 && !EMBEDDED