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 - "GeodeGX1" for Geode GX1 (Cyrix MediaGX).
187 - "CyrixIII/VIA C3" for VIA Cyrix III or VIA C3.
188 - "VIA C3-2 for VIA C3-2 "Nehemiah" (model 9 and above).
190 If you don't know what to do, choose "386".
195 Select this for a 486 series processor, either Intel or one of the
196 compatible processors from AMD, Cyrix, IBM, or Intel. Includes DX,
197 DX2, and DX4 variants; also SL/SLC/SLC2/SLC3/SX/SX2 and UMC U5D or
201 bool "586/K5/5x86/6x86/6x86MX"
203 Select this for an 586 or 686 series processor such as the AMD K5,
204 the Cyrix 5x86, 6x86 and 6x86MX. This choice does not
205 assume the RDTSC (Read Time Stamp Counter) instruction.
208 bool "Pentium-Classic"
210 Select this for a Pentium Classic processor with the RDTSC (Read
211 Time Stamp Counter) instruction for benchmarking.
216 Select this for a Pentium with the MMX graphics/multimedia
217 extended instructions.
222 Select this for Intel Pentium Pro chips. This enables the use of
223 Pentium Pro extended instructions, and disables the init-time guard
224 against the f00f bug found in earlier Pentiums.
227 bool "Pentium-II/Celeron(pre-Coppermine)"
229 Select this for Intel chips based on the Pentium-II and
230 pre-Coppermine Celeron core. This option enables an unaligned
231 copy optimization, compiles the kernel with optimization flags
232 tailored for the chip, and applies any applicable Pentium Pro
236 bool "Pentium-III/Celeron(Coppermine)/Pentium-III Xeon"
238 Select this for Intel chips based on the Pentium-III and
239 Celeron-Coppermine core. This option enables use of some
240 extended prefetch instructions in addition to the Pentium II
246 Select this for Intel Pentium M (not Pentium-4 M)
250 bool "Pentium-4/Celeron(P4-based)/Pentium-4 M/Xeon"
252 Select this for Intel Pentium 4 chips. This includes the
253 Pentium 4, P4-based Celeron and Xeon, and Pentium-4 M
254 (not Pentium M) chips. This option enables compile flags
255 optimized for the chip, uses the correct cache shift, and
256 applies any applicable Pentium III optimizations.
259 bool "K6/K6-II/K6-III"
261 Select this for an AMD K6-family processor. Enables use of
262 some extended instructions, and passes appropriate optimization
266 bool "Athlon/Duron/K7"
268 Select this for an AMD Athlon K7-family processor. Enables use of
269 some extended instructions, and passes appropriate optimization
273 bool "Opteron/Athlon64/Hammer/K8"
275 Select this for an AMD Opteron or Athlon64 Hammer-family processor. Enables
276 use of some extended instructions, and passes appropriate optimization
282 Select this for a Transmeta Crusoe processor. Treats the processor
283 like a 586 with TSC, and sets some GCC optimization flags (like a
284 Pentium Pro with no alignment requirements).
289 Select this for a Transmeta Efficeon processor.
294 Select this for an IDT Winchip C6 chip. Linux and GCC
295 treat this chip as a 586TSC with some extended instructions
296 and alignment requirements.
301 Select this for an IDT Winchip-2. Linux and GCC
302 treat this chip as a 586TSC with some extended instructions
303 and alignment requirements.
306 bool "Winchip-2A/Winchip-3"
308 Select this for an IDT Winchip-2A or 3. Linux and GCC
309 treat this chip as a 586TSC with some extended instructions
310 and alignment reqirements. Also enable out of order memory
311 stores for this CPU, which can increase performance of some
317 Select this for a Geode GX1 (Cyrix MediaGX) chip.
320 bool "CyrixIII/VIA-C3"
322 Select this for a Cyrix III or C3 chip. Presently Linux and GCC
323 treat this chip as a generic 586. Whilst the CPU is 686 class,
324 it lacks the cmov extension which gcc assumes is present when
326 Note that Nehemiah (Model 9) and above will not boot with this
327 kernel due to them lacking the 3DNow! instructions used in earlier
328 incarnations of the CPU.
331 bool "VIA C3-2 (Nehemiah)"
333 Select this for a VIA C3 "Nehemiah". Selecting this enables usage
334 of SSE and tells gcc to treat the CPU as a 686.
335 Note, this kernel will not boot on older (pre model 9) C3s.
340 bool "Generic x86 support"
342 Instead of just including optimizations for the selected
343 x86 variant (e.g. PII, Crusoe or Athlon), include some more
344 generic optimizations as well. This will make the kernel
345 perform better on x86 CPUs other than that selected.
347 This is really intended for distributors who need more
348 generic optimizations.
353 # Define implied options from the CPU selection here
365 config X86_L1_CACHE_SHIFT
367 default "7" if MPENTIUM4 || X86_GENERIC
368 default "4" if X86_ELAN || M486 || M386
369 default "5" if MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCRUSOE || MEFFICEON || MCYRIXIII || MK6 || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || M586 || MVIAC3_2 || MGEODEGX1
370 default "6" if MK7 || MK8 || MPENTIUMM
372 config RWSEM_GENERIC_SPINLOCK
377 config RWSEM_XCHGADD_ALGORITHM
382 config GENERIC_CALIBRATE_DELAY
386 config X86_PPRO_FENCE
388 depends on M686 || M586MMX || M586TSC || M586 || M486 || M386 || MGEODEGX1
393 depends on M586MMX || M586TSC || M586 || M486 || M386
396 config X86_WP_WORKS_OK
416 config X86_ALIGNMENT_16
418 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || X86_ELAN || MK6 || M586MMX || M586TSC || M586 || M486 || MVIAC3_2 || MGEODEGX1
423 depends on MK7 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || MK8 || MEFFICEON
426 config X86_INTEL_USERCOPY
428 depends on MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M586MMX || X86_GENERIC || MK8 || MK7 || MEFFICEON
431 config X86_USE_PPRO_CHECKSUM
433 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC3_2 || MEFFICEON
438 depends on MCYRIXIII || MK7
443 depends on (MWINCHIP3D || MWINCHIP2 || MWINCHIPC6) && MTRR
447 bool "HPET Timer Support"
449 This enables the use of the HPET for the kernel's internal timer.
450 HPET is the next generation timer replacing legacy 8254s.
451 You can safely choose Y here. However, HPET will only be
452 activated if the platform and the BIOS support this feature.
453 Otherwise the 8254 will be used for timing services.
455 Choose N to continue using the legacy 8254 timer.
457 config HPET_EMULATE_RTC
458 bool "Provide RTC interrupt"
459 depends on HPET_TIMER && RTC=y
462 bool "Symmetric multi-processing support"
464 This enables support for systems with more than one CPU. If you have
465 a system with only one CPU, like most personal computers, say N. If
466 you have a system with more than one CPU, say Y.
468 If you say N here, the kernel will run on single and multiprocessor
469 machines, but will use only one CPU of a multiprocessor machine. If
470 you say Y here, the kernel will run on many, but not all,
471 singleprocessor machines. On a singleprocessor machine, the kernel
472 will run faster if you say N here.
474 Note that if you say Y here and choose architecture "586" or
475 "Pentium" under "Processor family", the kernel will not work on 486
476 architectures. Similarly, multiprocessor kernels for the "PPro"
477 architecture may not work on all Pentium based boards.
479 People using multiprocessor machines who say Y here should also say
480 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
481 Management" code will be disabled if you say Y here.
483 See also the <file:Documentation/smp.txt>,
484 <file:Documentation/i386/IO-APIC.txt>,
485 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
486 <http://www.tldp.org/docs.html#howto>.
488 If you don't know what to do here, say N.
491 int "Maximum number of CPUs (2-255)"
494 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
497 This allows you to specify the maximum number of CPUs which this
498 kernel will support. The maximum supported value is 255 and the
499 minimum value which makes sense is 2.
501 This is purely to save memory - each supported CPU adds
502 approximately eight kilobytes to the kernel image.
505 bool "SMT (Hyperthreading) scheduler support"
509 SMT scheduler support improves the CPU scheduler's decision making
510 when dealing with Intel Pentium 4 chips with HyperThreading at a
511 cost of slightly increased overhead in some places. If unsure say
515 bool "Preemptible Kernel"
517 This option reduces the latency of the kernel when reacting to
518 real-time or interactive events by allowing a low priority process to
519 be preempted even if it is in kernel mode executing a system call.
520 This allows applications to run more reliably even when the system is
523 Say Y here if you are building a kernel for a desktop, embedded
524 or real-time system. Say N if you are unsure.
527 bool "Preempt The Big Kernel Lock"
531 This option reduces the latency of the kernel by making the
532 big kernel lock preemptible.
534 Say Y here if you are building a kernel for a desktop system.
535 Say N if you are unsure.
538 bool "Local APIC support on uniprocessors"
539 depends on !SMP && !(X86_VISWS || X86_VOYAGER)
541 A local APIC (Advanced Programmable Interrupt Controller) is an
542 integrated interrupt controller in the CPU. If you have a single-CPU
543 system which has a processor with a local APIC, you can say Y here to
544 enable and use it. If you say Y here even though your machine doesn't
545 have a local APIC, then the kernel will still run with no slowdown at
546 all. The local APIC supports CPU-generated self-interrupts (timer,
547 performance counters), and the NMI watchdog which detects hard
551 bool "IO-APIC support on uniprocessors"
552 depends on X86_UP_APIC
554 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
555 SMP-capable replacement for PC-style interrupt controllers. Most
556 SMP systems and many recent uniprocessor systems have one.
558 If you have a single-CPU system with an IO-APIC, you can say Y here
559 to use it. If you say Y here even though your machine doesn't have
560 an IO-APIC, then the kernel will still run with no slowdown at all.
562 config X86_LOCAL_APIC
564 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER)
569 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER))
572 config X86_VISWS_APIC
579 depends on (MWINCHIP3D || MWINCHIP2 || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2 || MGEODEGX1) && !X86_NUMAQ
583 bool "Machine Check Exception"
584 depends on !X86_VOYAGER
586 Machine Check Exception support allows the processor to notify the
587 kernel if it detects a problem (e.g. overheating, component failure).
588 The action the kernel takes depends on the severity of the problem,
589 ranging from a warning message on the console, to halting the machine.
590 Your processor must be a Pentium or newer to support this - check the
591 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
592 have a design flaw which leads to false MCE events - hence MCE is
593 disabled on all P5 processors, unless explicitly enabled with "mce"
594 as a boot argument. Similarly, if MCE is built in and creates a
595 problem on some new non-standard machine, you can boot with "nomce"
596 to disable it. MCE support simply ignores non-MCE processors like
597 the 386 and 486, so nearly everyone can say Y here.
599 config X86_MCE_NONFATAL
600 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
603 Enabling this feature starts a timer that triggers every 5 seconds which
604 will look at the machine check registers to see if anything happened.
605 Non-fatal problems automatically get corrected (but still logged).
606 Disable this if you don't want to see these messages.
607 Seeing the messages this option prints out may be indicative of dying hardware,
608 or out-of-spec (ie, overclocked) hardware.
609 This option only does something on certain CPUs.
610 (AMD Athlon/Duron and Intel Pentium 4)
612 config X86_MCE_P4THERMAL
613 bool "check for P4 thermal throttling interrupt."
614 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
616 Enabling this feature will cause a message to be printed when the P4
617 enters thermal throttling.
620 tristate "Toshiba Laptop support"
622 This adds a driver to safely access the System Management Mode of
623 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
624 not work on models with a Phoenix BIOS. The System Management Mode
625 is used to set the BIOS and power saving options on Toshiba portables.
627 For information on utilities to make use of this driver see the
628 Toshiba Linux utilities web site at:
629 <http://www.buzzard.org.uk/toshiba/>.
631 Say Y if you intend to run this kernel on a Toshiba portable.
635 tristate "Dell laptop support"
637 This adds a driver to safely access the System Management Mode
638 of the CPU on the Dell Inspiron 8000. The System Management Mode
639 is used to read cpu temperature and cooling fan status and to
640 control the fans on the I8K portables.
642 This driver has been tested only on the Inspiron 8000 but it may
643 also work with other Dell laptops. You can force loading on other
644 models by passing the parameter `force=1' to the module. Use at
647 For information on utilities to make use of this driver see the
648 I8K Linux utilities web site at:
649 <http://people.debian.org/~dz/i8k/>
651 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
654 config X86_REBOOTFIXUPS
655 bool "Enable X86 board specific fixups for reboot"
659 This enables chipset and/or board specific fixups to be done
660 in order to get reboot to work correctly. This is only needed on
661 some combinations of hardware and BIOS. The symptom, for which
662 this config is intended, is when reboot ends with a stalled/hung
665 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
668 Say Y if you want to enable the fixup. Currently, it's safe to
669 enable this option even if you don't need it.
673 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
675 If you say Y here and also to "/dev file system support" in the
676 'File systems' section, you will be able to update the microcode on
677 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
678 Pentium III, Pentium 4, Xeon etc. You will obviously need the
679 actual microcode binary data itself which is not shipped with the
682 For latest news and information on obtaining all the required
683 ingredients for this driver, check:
684 <http://www.urbanmyth.org/microcode/>.
686 To compile this driver as a module, choose M here: the
687 module will be called microcode.
690 tristate "/dev/cpu/*/msr - Model-specific register support"
692 This device gives privileged processes access to the x86
693 Model-Specific Registers (MSRs). It is a character device with
694 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
695 MSR accesses are directed to a specific CPU on multi-processor
699 tristate "/dev/cpu/*/cpuid - CPU information support"
701 This device gives processes access to the x86 CPUID instruction to
702 be executed on a specific processor. It is a character device
703 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
706 source "drivers/firmware/Kconfig"
709 prompt "High Memory Support"
715 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
716 However, the address space of 32-bit x86 processors is only 4
717 Gigabytes large. That means that, if you have a large amount of
718 physical memory, not all of it can be "permanently mapped" by the
719 kernel. The physical memory that's not permanently mapped is called
722 If you are compiling a kernel which will never run on a machine with
723 more than 1 Gigabyte total physical RAM, answer "off" here (default
724 choice and suitable for most users). This will result in a "3GB/1GB"
725 split: 3GB are mapped so that each process sees a 3GB virtual memory
726 space and the remaining part of the 4GB virtual memory space is used
727 by the kernel to permanently map as much physical memory as
730 If the machine has between 1 and 4 Gigabytes physical RAM, then
733 If more than 4 Gigabytes is used then answer "64GB" here. This
734 selection turns Intel PAE (Physical Address Extension) mode on.
735 PAE implements 3-level paging on IA32 processors. PAE is fully
736 supported by Linux, PAE mode is implemented on all recent Intel
737 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
738 then the kernel will not boot on CPUs that don't support PAE!
740 The actual amount of total physical memory will either be
741 auto detected or can be forced by using a kernel command line option
742 such as "mem=256M". (Try "man bootparam" or see the documentation of
743 your boot loader (lilo or loadlin) about how to pass options to the
744 kernel at boot time.)
746 If unsure, say "off".
751 Select this if you have a 32-bit processor and between 1 and 4
752 gigabytes of physical RAM.
757 Select this if you have a 32-bit processor and more than 4
758 gigabytes of physical RAM.
764 depends on HIGHMEM64G || HIGHMEM4G
769 depends on HIGHMEM64G
772 # Common NUMA Features
774 bool "Numa Memory Allocation and Scheduler Support"
775 depends on SMP && HIGHMEM64G && (X86_NUMAQ || X86_GENERICARCH || (X86_SUMMIT && ACPI))
777 default y if (X86_NUMAQ || X86_SUMMIT)
779 # Need comments to help the hapless user trying to turn on NUMA support
780 comment "NUMA (NUMA-Q) requires SMP, 64GB highmem support"
781 depends on X86_NUMAQ && (!HIGHMEM64G || !SMP)
783 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
784 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
791 config HAVE_ARCH_BOOTMEM_NODE
796 config HAVE_MEMORY_PRESENT
798 depends on DISCONTIGMEM
801 config NEED_NODE_MEMMAP_SIZE
803 depends on DISCONTIGMEM
807 bool "Allocate 3rd-level pagetables from highmem"
808 depends on HIGHMEM4G || HIGHMEM64G
810 The VM uses one page table entry for each page of physical memory.
811 For systems with a lot of RAM, this can be wasteful of precious
812 low memory. Setting this option will put user-space page table
813 entries in high memory.
815 config MATH_EMULATION
816 bool "Math emulation"
818 Linux can emulate a math coprocessor (used for floating point
819 operations) if you don't have one. 486DX and Pentium processors have
820 a math coprocessor built in, 486SX and 386 do not, unless you added
821 a 487DX or 387, respectively. (The messages during boot time can
822 give you some hints here ["man dmesg"].) Everyone needs either a
823 coprocessor or this emulation.
825 If you don't have a math coprocessor, you need to say Y here; if you
826 say Y here even though you have a coprocessor, the coprocessor will
827 be used nevertheless. (This behavior can be changed with the kernel
828 command line option "no387", which comes handy if your coprocessor
829 is broken. Try "man bootparam" or see the documentation of your boot
830 loader (lilo or loadlin) about how to pass options to the kernel at
831 boot time.) This means that it is a good idea to say Y here if you
832 intend to use this kernel on different machines.
834 More information about the internals of the Linux math coprocessor
835 emulation can be found in <file:arch/i386/math-emu/README>.
837 If you are not sure, say Y; apart from resulting in a 66 KB bigger
838 kernel, it won't hurt.
841 bool "MTRR (Memory Type Range Register) support"
843 On Intel P6 family processors (Pentium Pro, Pentium II and later)
844 the Memory Type Range Registers (MTRRs) may be used to control
845 processor access to memory ranges. This is most useful if you have
846 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
847 allows bus write transfers to be combined into a larger transfer
848 before bursting over the PCI/AGP bus. This can increase performance
849 of image write operations 2.5 times or more. Saying Y here creates a
850 /proc/mtrr file which may be used to manipulate your processor's
851 MTRRs. Typically the X server should use this.
853 This code has a reasonably generic interface so that similar
854 control registers on other processors can be easily supported
857 The Cyrix 6x86, 6x86MX and M II processors have Address Range
858 Registers (ARRs) which provide a similar functionality to MTRRs. For
859 these, the ARRs are used to emulate the MTRRs.
860 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
861 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
862 write-combining. All of these processors are supported by this code
863 and it makes sense to say Y here if you have one of them.
865 Saying Y here also fixes a problem with buggy SMP BIOSes which only
866 set the MTRRs for the boot CPU and not for the secondary CPUs. This
867 can lead to all sorts of problems, so it's good to say Y here.
869 You can safely say Y even if your machine doesn't have MTRRs, you'll
870 just add about 9 KB to your kernel.
872 See <file:Documentation/mtrr.txt> for more information.
875 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 a 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
926 bool "Enable seccomp to safely compute untrusted bytecode"
930 This kernel feature is useful for number crunching applications
931 that may need to compute untrusted bytecode during their
932 execution. By using pipes or other transports made available to
933 the process as file descriptors supporting the read/write
934 syscalls, it's possible to isolate those applications in
935 their own address space using seccomp. Once seccomp is
936 enabled via /proc/<pid>/seccomp, it cannot be disabled
937 and the task is only allowed to execute a few safe syscalls
938 defined by each seccomp mode.
940 If unsure, say Y. Only embedded should say N here.
945 menu "Power management options (ACPI, APM)"
946 depends on !X86_VOYAGER
948 source kernel/power/Kconfig
950 source "drivers/acpi/Kconfig"
952 menu "APM (Advanced Power Management) BIOS Support"
953 depends on PM && !X86_VISWS
956 tristate "APM (Advanced Power Management) BIOS support"
959 APM is a BIOS specification for saving power using several different
960 techniques. This is mostly useful for battery powered laptops with
961 APM compliant BIOSes. If you say Y here, the system time will be
962 reset after a RESUME operation, the /proc/apm device will provide
963 battery status information, and user-space programs will receive
964 notification of APM "events" (e.g. battery status change).
966 If you select "Y" here, you can disable actual use of the APM
967 BIOS by passing the "apm=off" option to the kernel at boot time.
969 Note that the APM support is almost completely disabled for
970 machines with more than one CPU.
972 In order to use APM, you will need supporting software. For location
973 and more information, read <file:Documentation/pm.txt> and the
974 Battery Powered Linux mini-HOWTO, available from
975 <http://www.tldp.org/docs.html#howto>.
977 This driver does not spin down disk drives (see the hdparm(8)
978 manpage ("man 8 hdparm") for that), and it doesn't turn off
979 VESA-compliant "green" monitors.
981 This driver does not support the TI 4000M TravelMate and the ACER
982 486/DX4/75 because they don't have compliant BIOSes. Many "green"
983 desktop machines also don't have compliant BIOSes, and this driver
984 may cause those machines to panic during the boot phase.
986 Generally, if you don't have a battery in your machine, there isn't
987 much point in using this driver and you should say N. If you get
988 random kernel OOPSes or reboots that don't seem to be related to
989 anything, try disabling/enabling this option (or disabling/enabling
992 Some other things you should try when experiencing seemingly random,
995 1) make sure that you have enough swap space and that it is
997 2) pass the "no-hlt" option to the kernel
998 3) switch on floating point emulation in the kernel and pass
999 the "no387" option to the kernel
1000 4) pass the "floppy=nodma" option to the kernel
1001 5) pass the "mem=4M" option to the kernel (thereby disabling
1002 all but the first 4 MB of RAM)
1003 6) make sure that the CPU is not over clocked.
1004 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1005 8) disable the cache from your BIOS settings
1006 9) install a fan for the video card or exchange video RAM
1007 10) install a better fan for the CPU
1008 11) exchange RAM chips
1009 12) exchange the motherboard.
1011 To compile this driver as a module, choose M here: the
1012 module will be called apm.
1014 config APM_IGNORE_USER_SUSPEND
1015 bool "Ignore USER SUSPEND"
1018 This option will ignore USER SUSPEND requests. On machines with a
1019 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1020 series notebooks, it is necessary to say Y because of a BIOS bug.
1022 config APM_DO_ENABLE
1023 bool "Enable PM at boot time"
1026 Enable APM features at boot time. From page 36 of the APM BIOS
1027 specification: "When disabled, the APM BIOS does not automatically
1028 power manage devices, enter the Standby State, enter the Suspend
1029 State, or take power saving steps in response to CPU Idle calls."
1030 This driver will make CPU Idle calls when Linux is idle (unless this
1031 feature is turned off -- see "Do CPU IDLE calls", below). This
1032 should always save battery power, but more complicated APM features
1033 will be dependent on your BIOS implementation. You may need to turn
1034 this option off if your computer hangs at boot time when using APM
1035 support, or if it beeps continuously instead of suspending. Turn
1036 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1037 T400CDT. This is off by default since most machines do fine without
1041 bool "Make CPU Idle calls when idle"
1044 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1045 On some machines, this can activate improved power savings, such as
1046 a slowed CPU clock rate, when the machine is idle. These idle calls
1047 are made after the idle loop has run for some length of time (e.g.,
1048 333 mS). On some machines, this will cause a hang at boot time or
1049 whenever the CPU becomes idle. (On machines with more than one CPU,
1050 this option does nothing.)
1052 config APM_DISPLAY_BLANK
1053 bool "Enable console blanking using APM"
1056 Enable console blanking using the APM. Some laptops can use this to
1057 turn off the LCD backlight when the screen blanker of the Linux
1058 virtual console blanks the screen. Note that this is only used by
1059 the virtual console screen blanker, and won't turn off the backlight
1060 when using the X Window system. This also doesn't have anything to
1061 do with your VESA-compliant power-saving monitor. Further, this
1062 option doesn't work for all laptops -- it might not turn off your
1063 backlight at all, or it might print a lot of errors to the console,
1064 especially if you are using gpm.
1066 config APM_RTC_IS_GMT
1067 bool "RTC stores time in GMT"
1070 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
1071 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
1074 It is in fact recommended to store GMT in your RTC, because then you
1075 don't have to worry about daylight savings time changes. The only
1076 reason not to use GMT in your RTC is if you also run a broken OS
1077 that doesn't understand GMT.
1079 config APM_ALLOW_INTS
1080 bool "Allow interrupts during APM BIOS calls"
1083 Normally we disable external interrupts while we are making calls to
1084 the APM BIOS as a measure to lessen the effects of a badly behaving
1085 BIOS implementation. The BIOS should reenable interrupts if it
1086 needs to. Unfortunately, some BIOSes do not -- especially those in
1087 many of the newer IBM Thinkpads. If you experience hangs when you
1088 suspend, try setting this to Y. Otherwise, say N.
1090 config APM_REAL_MODE_POWER_OFF
1091 bool "Use real mode APM BIOS call to power off"
1094 Use real mode APM BIOS calls to switch off the computer. This is
1095 a work-around for a number of buggy BIOSes. Switch this option on if
1096 your computer crashes instead of powering off properly.
1100 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1104 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1107 bool "PCI support" if !X86_VISWS
1108 depends on !X86_VOYAGER
1109 default y if X86_VISWS
1111 Find out whether you have a PCI motherboard. PCI is the name of a
1112 bus system, i.e. the way the CPU talks to the other stuff inside
1113 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1114 VESA. If you have PCI, say Y, otherwise N.
1116 The PCI-HOWTO, available from
1117 <http://www.tldp.org/docs.html#howto>, contains valuable
1118 information about which PCI hardware does work under Linux and which
1122 prompt "PCI access mode"
1123 depends on PCI && !X86_VISWS
1126 On PCI systems, the BIOS can be used to detect the PCI devices and
1127 determine their configuration. However, some old PCI motherboards
1128 have BIOS bugs and may crash if this is done. Also, some embedded
1129 PCI-based systems don't have any BIOS at all. Linux can also try to
1130 detect the PCI hardware directly without using the BIOS.
1132 With this option, you can specify how Linux should detect the
1133 PCI devices. If you choose "BIOS", the BIOS will be used,
1134 if you choose "Direct", the BIOS won't be used, and if you
1135 choose "MMConfig", then PCI Express MMCONFIG will be used.
1136 If you choose "Any", the kernel will try MMCONFIG, then the
1137 direct access method and falls back to the BIOS if that doesn't
1138 work. If unsure, go with the default, which is "Any".
1143 config PCI_GOMMCONFIG
1156 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1161 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1166 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1170 source "drivers/pci/pcie/Kconfig"
1172 source "drivers/pci/Kconfig"
1180 depends on !(X86_VOYAGER || X86_VISWS)
1182 Find out whether you have ISA slots on your motherboard. ISA is the
1183 name of a bus system, i.e. the way the CPU talks to the other stuff
1184 inside your box. Other bus systems are PCI, EISA, MicroChannel
1185 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1186 newer boards don't support it. If you have ISA, say Y, otherwise N.
1192 The Extended Industry Standard Architecture (EISA) bus was
1193 developed as an open alternative to the IBM MicroChannel bus.
1195 The EISA bus provided some of the features of the IBM MicroChannel
1196 bus while maintaining backward compatibility with cards made for
1197 the older ISA bus. The EISA bus saw limited use between 1988 and
1198 1995 when it was made obsolete by the PCI bus.
1200 Say Y here if you are building a kernel for an EISA-based machine.
1204 source "drivers/eisa/Kconfig"
1207 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1208 default y if X86_VOYAGER
1210 MicroChannel Architecture is found in some IBM PS/2 machines and
1211 laptops. It is a bus system similar to PCI or ISA. See
1212 <file:Documentation/mca.txt> (and especially the web page given
1213 there) before attempting to build an MCA bus kernel.
1215 source "drivers/mca/Kconfig"
1218 tristate "NatSemi SCx200 support"
1219 depends on !X86_VOYAGER
1221 This provides basic support for the National Semiconductor SCx200
1222 processor. Right now this is just a driver for the GPIO pins.
1224 If you don't know what to do here, say N.
1226 This support is also available as a module. If compiled as a
1227 module, it will be called scx200.
1229 source "drivers/pcmcia/Kconfig"
1231 source "drivers/pci/hotplug/Kconfig"
1235 menu "Executable file formats"
1237 source "fs/Kconfig.binfmt"
1241 source "drivers/Kconfig"
1245 source "arch/i386/oprofile/Kconfig"
1247 source "arch/i386/Kconfig.debug"
1249 source "security/Kconfig"
1251 source "crypto/Kconfig"
1253 source "lib/Kconfig"
1256 # Use the generic interrupt handling code in kernel/irq/:
1258 config GENERIC_HARDIRQS
1262 config GENERIC_IRQ_PROBE
1268 depends on SMP && !X86_VOYAGER
1273 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1276 config X86_BIOS_REBOOT
1278 depends on !(X86_VISWS || X86_VOYAGER)
1281 config X86_TRAMPOLINE
1283 depends on X86_SMP || (X86_VOYAGER && SMP)
1288 depends on X86 && !EMBEDDED
projects / linux-2.6 / blob