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 - "MediaGX/Geode" for Cyrix MediaGX aka Geode.
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 Cyrix MediaGX aka Geode chip. Linux and GCC
318 treat this chip as a 586TSC with some extended instructions
319 and alignment reqirements.
322 bool "CyrixIII/VIA-C3"
324 Select this for a Cyrix III or C3 chip. Presently Linux and GCC
325 treat this chip as a generic 586. Whilst the CPU is 686 class,
326 it lacks the cmov extension which gcc assumes is present when
328 Note that Nehemiah (Model 9) and above will not boot with this
329 kernel due to them lacking the 3DNow! instructions used in earlier
330 incarnations of the CPU.
333 bool "VIA C3-2 (Nehemiah)"
335 Select this for a VIA C3 "Nehemiah". Selecting this enables usage
336 of SSE and tells gcc to treat the CPU as a 686.
337 Note, this kernel will not boot on older (pre model 9) C3s.
342 bool "Generic x86 support"
344 Instead of just including optimizations for the selected
345 x86 variant (e.g. PII, Crusoe or Athlon), include some more
346 generic optimizations as well. This will make the kernel
347 perform better on x86 CPUs other than that selected.
349 This is really intended for distributors who need more
350 generic optimizations.
355 # Define implied options from the CPU selection here
367 config X86_L1_CACHE_SHIFT
369 default "7" if MPENTIUM4 || X86_GENERIC
370 default "4" if X86_ELAN || M486 || M386
371 default "5" if MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCRUSOE || MEFFICEON || MCYRIXIII || MK6 || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || M586 || MVIAC3_2 || MGEODE
372 default "6" if MK7 || MK8 || MPENTIUMM
374 config RWSEM_GENERIC_SPINLOCK
379 config RWSEM_XCHGADD_ALGORITHM
384 config GENERIC_CALIBRATE_DELAY
388 config X86_PPRO_FENCE
390 depends on M686 || M586MMX || M586TSC || M586 || M486 || M386 || MGEODE
395 depends on M586MMX || M586TSC || M586 || M486 || M386
398 config X86_WP_WORKS_OK
418 config X86_ALIGNMENT_16
420 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || X86_ELAN || MK6 || M586MMX || M586TSC || M586 || M486 || MVIAC3_2 || MGEODE
425 depends on MK7 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || MK8 || MEFFICEON
428 config X86_INTEL_USERCOPY
430 depends on MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M586MMX || X86_GENERIC || MK8 || MK7 || MEFFICEON
433 config X86_USE_PPRO_CHECKSUM
435 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC3_2 || MEFFICEON
440 depends on MCYRIXIII || MK7
445 depends on (MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MGEODE) && MTRR
449 bool "HPET Timer Support"
451 This enables the use of the HPET for the kernel's internal timer.
452 HPET is the next generation timer replacing legacy 8254s.
453 You can safely choose Y here. However, HPET will only be
454 activated if the platform and the BIOS support this feature.
455 Otherwise the 8254 will be used for timing services.
457 Choose N to continue using the legacy 8254 timer.
459 config HPET_EMULATE_RTC
460 bool "Provide RTC interrupt"
461 depends on HPET_TIMER && RTC=y
464 bool "Symmetric multi-processing support"
466 This enables support for systems with more than one CPU. If you have
467 a system with only one CPU, like most personal computers, say N. If
468 you have a system with more than one CPU, say Y.
470 If you say N here, the kernel will run on single and multiprocessor
471 machines, but will use only one CPU of a multiprocessor machine. If
472 you say Y here, the kernel will run on many, but not all,
473 singleprocessor machines. On a singleprocessor machine, the kernel
474 will run faster if you say N here.
476 Note that if you say Y here and choose architecture "586" or
477 "Pentium" under "Processor family", the kernel will not work on 486
478 architectures. Similarly, multiprocessor kernels for the "PPro"
479 architecture may not work on all Pentium based boards.
481 People using multiprocessor machines who say Y here should also say
482 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
483 Management" code will be disabled if you say Y here.
485 See also the <file:Documentation/smp.txt>,
486 <file:Documentation/i386/IO-APIC.txt>,
487 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
488 <http://www.tldp.org/docs.html#howto>.
490 If you don't know what to do here, say N.
493 int "Maximum number of CPUs (2-255)"
496 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
499 This allows you to specify the maximum number of CPUs which this
500 kernel will support. The maximum supported value is 255 and the
501 minimum value which makes sense is 2.
503 This is purely to save memory - each supported CPU adds
504 approximately eight kilobytes to the kernel image.
507 bool "SMT (Hyperthreading) scheduler support"
511 SMT scheduler support improves the CPU scheduler's decision making
512 when dealing with Intel Pentium 4 chips with HyperThreading at a
513 cost of slightly increased overhead in some places. If unsure say
517 bool "Preemptible Kernel"
519 This option reduces the latency of the kernel when reacting to
520 real-time or interactive events by allowing a low priority process to
521 be preempted even if it is in kernel mode executing a system call.
522 This allows applications to run more reliably even when the system is
525 Say Y here if you are building a kernel for a desktop, embedded
526 or real-time system. Say N if you are unsure.
529 bool "Preempt The Big Kernel Lock"
533 This option reduces the latency of the kernel by making the
534 big kernel lock preemptible.
536 Say Y here if you are building a kernel for a desktop system.
537 Say N if you are unsure.
540 bool "Local APIC support on uniprocessors"
541 depends on !SMP && !(X86_VISWS || X86_VOYAGER)
543 A local APIC (Advanced Programmable Interrupt Controller) is an
544 integrated interrupt controller in the CPU. If you have a single-CPU
545 system which has a processor with a local APIC, you can say Y here to
546 enable and use it. If you say Y here even though your machine doesn't
547 have a local APIC, then the kernel will still run with no slowdown at
548 all. The local APIC supports CPU-generated self-interrupts (timer,
549 performance counters), and the NMI watchdog which detects hard
553 bool "IO-APIC support on uniprocessors"
554 depends on X86_UP_APIC
556 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
557 SMP-capable replacement for PC-style interrupt controllers. Most
558 SMP systems and many recent uniprocessor systems have one.
560 If you have a single-CPU system with an IO-APIC, you can say Y here
561 to use it. If you say Y here even though your machine doesn't have
562 an IO-APIC, then the kernel will still run with no slowdown at all.
564 config X86_LOCAL_APIC
566 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER)
571 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER))
574 config X86_VISWS_APIC
581 depends on (MWINCHIP3D || MWINCHIP2 || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2 || MGEODE) && !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.
748 depends on HIGHMEM64G || HIGHMEM4G
753 depends on HIGHMEM64G
756 # Common NUMA Features
758 bool "Numa Memory Allocation and Scheduler Support"
759 depends on SMP && HIGHMEM64G && (X86_NUMAQ || X86_GENERICARCH || (X86_SUMMIT && ACPI))
761 default y if (X86_NUMAQ || X86_SUMMIT)
763 # Need comments to help the hapless user trying to turn on NUMA support
764 comment "NUMA (NUMA-Q) requires SMP, 64GB highmem support"
765 depends on X86_NUMAQ && (!HIGHMEM64G || !SMP)
767 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
768 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
775 config HAVE_ARCH_BOOTMEM_NODE
780 config HAVE_MEMORY_PRESENT
782 depends on DISCONTIGMEM
785 config NEED_NODE_MEMMAP_SIZE
787 depends on DISCONTIGMEM
791 bool "Allocate 3rd-level pagetables from highmem"
792 depends on HIGHMEM4G || HIGHMEM64G
794 The VM uses one page table entry for each page of physical memory.
795 For systems with a lot of RAM, this can be wasteful of precious
796 low memory. Setting this option will put user-space page table
797 entries in high memory.
799 config MATH_EMULATION
800 bool "Math emulation"
802 Linux can emulate a math coprocessor (used for floating point
803 operations) if you don't have one. 486DX and Pentium processors have
804 a math coprocessor built in, 486SX and 386 do not, unless you added
805 a 487DX or 387, respectively. (The messages during boot time can
806 give you some hints here ["man dmesg"].) Everyone needs either a
807 coprocessor or this emulation.
809 If you don't have a math coprocessor, you need to say Y here; if you
810 say Y here even though you have a coprocessor, the coprocessor will
811 be used nevertheless. (This behavior can be changed with the kernel
812 command line option "no387", which comes handy if your coprocessor
813 is broken. Try "man bootparam" or see the documentation of your boot
814 loader (lilo or loadlin) about how to pass options to the kernel at
815 boot time.) This means that it is a good idea to say Y here if you
816 intend to use this kernel on different machines.
818 More information about the internals of the Linux math coprocessor
819 emulation can be found in <file:arch/i386/math-emu/README>.
821 If you are not sure, say Y; apart from resulting in a 66 KB bigger
822 kernel, it won't hurt.
825 bool "MTRR (Memory Type Range Register) support"
827 On Intel P6 family processors (Pentium Pro, Pentium II and later)
828 the Memory Type Range Registers (MTRRs) may be used to control
829 processor access to memory ranges. This is most useful if you have
830 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
831 allows bus write transfers to be combined into a larger transfer
832 before bursting over the PCI/AGP bus. This can increase performance
833 of image write operations 2.5 times or more. Saying Y here creates a
834 /proc/mtrr file which may be used to manipulate your processor's
835 MTRRs. Typically the X server should use this.
837 This code has a reasonably generic interface so that similar
838 control registers on other processors can be easily supported
841 The Cyrix 6x86, 6x86MX and M II processors have Address Range
842 Registers (ARRs) which provide a similar functionality to MTRRs. For
843 these, the ARRs are used to emulate the MTRRs.
844 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
845 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
846 write-combining. All of these processors are supported by this code
847 and it makes sense to say Y here if you have one of them.
849 Saying Y here also fixes a problem with buggy SMP BIOSes which only
850 set the MTRRs for the boot CPU and not for the secondary CPUs. This
851 can lead to all sorts of problems, so it's good to say Y here.
853 You can safely say Y even if your machine doesn't have MTRRs, you'll
854 just add about 9 KB to your kernel.
856 See <file:Documentation/mtrr.txt> for more information.
859 bool "Boot from EFI support (EXPERIMENTAL)"
863 This enables the the kernel to boot on EFI platforms using
864 system configuration information passed to it from the firmware.
865 This also enables the kernel to use any EFI runtime services that are
866 available (such as the EFI variable services).
868 This option is only useful on systems that have EFI firmware
869 and will result in a kernel image that is ~8k larger. In addition,
870 you must use the latest ELILO loader available at
871 <http://elilo.sourceforge.net> in order to take advantage of
872 kernel initialization using EFI information (neither GRUB nor LILO know
873 anything about EFI). However, even with this option, the resultant
874 kernel should continue to boot on existing non-EFI platforms.
877 bool "Enable kernel irq balancing"
878 depends on SMP && X86_IO_APIC
881 The default yes will allow the kernel to do irq load balancing.
882 Saying no will keep the kernel from doing irq load balancing.
886 depends on (SMP || PREEMPT) && X86_CMPXCHG
889 # turning this on wastes a bunch of space.
890 # Summit needs it only when NUMA is on
893 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
897 bool "Use register arguments (EXPERIMENTAL)"
898 depends on EXPERIMENTAL
901 Compile the kernel with -mregparm=3. This uses a different ABI
902 and passes the first three arguments of a function call in registers.
903 This will probably break binary only modules.
905 This feature is only enabled for gcc-3.0 and later - earlier compilers
906 generate incorrect output with certain kernel constructs when
910 bool "Enable seccomp to safely compute untrusted bytecode"
914 This kernel feature is useful for number crunching applications
915 that may need to compute untrusted bytecode during their
916 execution. By using pipes or other transports made available to
917 the process as file descriptors supporting the read/write
918 syscalls, it's possible to isolate those applications in
919 their own address space using seccomp. Once seccomp is
920 enabled via /proc/<pid>/seccomp, it cannot be disabled
921 and the task is only allowed to execute a few safe syscalls
922 defined by each seccomp mode.
924 If unsure, say Y. Only embedded should say N here.
929 menu "Power management options (ACPI, APM)"
930 depends on !X86_VOYAGER
932 source kernel/power/Kconfig
934 source "drivers/acpi/Kconfig"
936 menu "APM (Advanced Power Management) BIOS Support"
937 depends on PM && !X86_VISWS
940 tristate "APM (Advanced Power Management) BIOS support"
943 APM is a BIOS specification for saving power using several different
944 techniques. This is mostly useful for battery powered laptops with
945 APM compliant BIOSes. If you say Y here, the system time will be
946 reset after a RESUME operation, the /proc/apm device will provide
947 battery status information, and user-space programs will receive
948 notification of APM "events" (e.g. battery status change).
950 If you select "Y" here, you can disable actual use of the APM
951 BIOS by passing the "apm=off" option to the kernel at boot time.
953 Note that the APM support is almost completely disabled for
954 machines with more than one CPU.
956 In order to use APM, you will need supporting software. For location
957 and more information, read <file:Documentation/pm.txt> and the
958 Battery Powered Linux mini-HOWTO, available from
959 <http://www.tldp.org/docs.html#howto>.
961 This driver does not spin down disk drives (see the hdparm(8)
962 manpage ("man 8 hdparm") for that), and it doesn't turn off
963 VESA-compliant "green" monitors.
965 This driver does not support the TI 4000M TravelMate and the ACER
966 486/DX4/75 because they don't have compliant BIOSes. Many "green"
967 desktop machines also don't have compliant BIOSes, and this driver
968 may cause those machines to panic during the boot phase.
970 Generally, if you don't have a battery in your machine, there isn't
971 much point in using this driver and you should say N. If you get
972 random kernel OOPSes or reboots that don't seem to be related to
973 anything, try disabling/enabling this option (or disabling/enabling
976 Some other things you should try when experiencing seemingly random,
979 1) make sure that you have enough swap space and that it is
981 2) pass the "no-hlt" option to the kernel
982 3) switch on floating point emulation in the kernel and pass
983 the "no387" option to the kernel
984 4) pass the "floppy=nodma" option to the kernel
985 5) pass the "mem=4M" option to the kernel (thereby disabling
986 all but the first 4 MB of RAM)
987 6) make sure that the CPU is not over clocked.
988 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
989 8) disable the cache from your BIOS settings
990 9) install a fan for the video card or exchange video RAM
991 10) install a better fan for the CPU
992 11) exchange RAM chips
993 12) exchange the motherboard.
995 To compile this driver as a module, choose M here: the
996 module will be called apm.
998 config APM_IGNORE_USER_SUSPEND
999 bool "Ignore USER SUSPEND"
1002 This option will ignore USER SUSPEND requests. On machines with a
1003 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1004 series notebooks, it is necessary to say Y because of a BIOS bug.
1006 config APM_DO_ENABLE
1007 bool "Enable PM at boot time"
1010 Enable APM features at boot time. From page 36 of the APM BIOS
1011 specification: "When disabled, the APM BIOS does not automatically
1012 power manage devices, enter the Standby State, enter the Suspend
1013 State, or take power saving steps in response to CPU Idle calls."
1014 This driver will make CPU Idle calls when Linux is idle (unless this
1015 feature is turned off -- see "Do CPU IDLE calls", below). This
1016 should always save battery power, but more complicated APM features
1017 will be dependent on your BIOS implementation. You may need to turn
1018 this option off if your computer hangs at boot time when using APM
1019 support, or if it beeps continuously instead of suspending. Turn
1020 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1021 T400CDT. This is off by default since most machines do fine without
1025 bool "Make CPU Idle calls when idle"
1028 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1029 On some machines, this can activate improved power savings, such as
1030 a slowed CPU clock rate, when the machine is idle. These idle calls
1031 are made after the idle loop has run for some length of time (e.g.,
1032 333 mS). On some machines, this will cause a hang at boot time or
1033 whenever the CPU becomes idle. (On machines with more than one CPU,
1034 this option does nothing.)
1036 config APM_DISPLAY_BLANK
1037 bool "Enable console blanking using APM"
1040 Enable console blanking using the APM. Some laptops can use this to
1041 turn off the LCD backlight when the screen blanker of the Linux
1042 virtual console blanks the screen. Note that this is only used by
1043 the virtual console screen blanker, and won't turn off the backlight
1044 when using the X Window system. This also doesn't have anything to
1045 do with your VESA-compliant power-saving monitor. Further, this
1046 option doesn't work for all laptops -- it might not turn off your
1047 backlight at all, or it might print a lot of errors to the console,
1048 especially if you are using gpm.
1050 config APM_RTC_IS_GMT
1051 bool "RTC stores time in GMT"
1054 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
1055 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
1058 It is in fact recommended to store GMT in your RTC, because then you
1059 don't have to worry about daylight savings time changes. The only
1060 reason not to use GMT in your RTC is if you also run a broken OS
1061 that doesn't understand GMT.
1063 config APM_ALLOW_INTS
1064 bool "Allow interrupts during APM BIOS calls"
1067 Normally we disable external interrupts while we are making calls to
1068 the APM BIOS as a measure to lessen the effects of a badly behaving
1069 BIOS implementation. The BIOS should reenable interrupts if it
1070 needs to. Unfortunately, some BIOSes do not -- especially those in
1071 many of the newer IBM Thinkpads. If you experience hangs when you
1072 suspend, try setting this to Y. Otherwise, say N.
1074 config APM_REAL_MODE_POWER_OFF
1075 bool "Use real mode APM BIOS call to power off"
1078 Use real mode APM BIOS calls to switch off the computer. This is
1079 a work-around for a number of buggy BIOSes. Switch this option on if
1080 your computer crashes instead of powering off properly.
1084 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1088 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1091 bool "PCI support" if !X86_VISWS
1092 depends on !X86_VOYAGER
1093 default y if X86_VISWS
1095 Find out whether you have a PCI motherboard. PCI is the name of a
1096 bus system, i.e. the way the CPU talks to the other stuff inside
1097 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1098 VESA. If you have PCI, say Y, otherwise N.
1100 The PCI-HOWTO, available from
1101 <http://www.tldp.org/docs.html#howto>, contains valuable
1102 information about which PCI hardware does work under Linux and which
1106 prompt "PCI access mode"
1107 depends on PCI && !X86_VISWS
1110 On PCI systems, the BIOS can be used to detect the PCI devices and
1111 determine their configuration. However, some old PCI motherboards
1112 have BIOS bugs and may crash if this is done. Also, some embedded
1113 PCI-based systems don't have any BIOS at all. Linux can also try to
1114 detect the PCI hardware directly without using the BIOS.
1116 With this option, you can specify how Linux should detect the
1117 PCI devices. If you choose "BIOS", the BIOS will be used,
1118 if you choose "Direct", the BIOS won't be used, and if you
1119 choose "MMConfig", then PCI Express MMCONFIG will be used.
1120 If you choose "Any", the kernel will try MMCONFIG, then the
1121 direct access method and falls back to the BIOS if that doesn't
1122 work. If unsure, go with the default, which is "Any".
1127 config PCI_GOMMCONFIG
1140 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1145 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1150 depends on PCI && (PCI_GOMMCONFIG || (PCI_GOANY && ACPI))
1154 source "drivers/pci/pcie/Kconfig"
1156 source "drivers/pci/Kconfig"
1160 depends on !(X86_VOYAGER || X86_VISWS)
1162 Find out whether you have ISA slots on your motherboard. ISA is the
1163 name of a bus system, i.e. the way the CPU talks to the other stuff
1164 inside your box. Other bus systems are PCI, EISA, MicroChannel
1165 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1166 newer boards don't support it. If you have ISA, say Y, otherwise N.
1172 The Extended Industry Standard Architecture (EISA) bus was
1173 developed as an open alternative to the IBM MicroChannel bus.
1175 The EISA bus provided some of the features of the IBM MicroChannel
1176 bus while maintaining backward compatibility with cards made for
1177 the older ISA bus. The EISA bus saw limited use between 1988 and
1178 1995 when it was made obsolete by the PCI bus.
1180 Say Y here if you are building a kernel for an EISA-based machine.
1184 source "drivers/eisa/Kconfig"
1187 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1188 default y if X86_VOYAGER
1190 MicroChannel Architecture is found in some IBM PS/2 machines and
1191 laptops. It is a bus system similar to PCI or ISA. See
1192 <file:Documentation/mca.txt> (and especially the web page given
1193 there) before attempting to build an MCA bus kernel.
1195 source "drivers/mca/Kconfig"
1198 tristate "NatSemi SCx200 support"
1199 depends on !X86_VOYAGER
1201 This provides basic support for the National Semiconductor SCx200
1202 processor. Right now this is just a driver for the GPIO pins.
1204 If you don't know what to do here, say N.
1206 This support is also available as a module. If compiled as a
1207 module, it will be called scx200.
1209 source "drivers/pcmcia/Kconfig"
1211 source "drivers/pci/hotplug/Kconfig"
1215 menu "Executable file formats"
1217 source "fs/Kconfig.binfmt"
1221 source "drivers/Kconfig"
1225 source "arch/i386/oprofile/Kconfig"
1227 source "arch/i386/Kconfig.debug"
1229 source "security/Kconfig"
1231 source "crypto/Kconfig"
1233 source "lib/Kconfig"
1236 # Use the generic interrupt handling code in kernel/irq/:
1238 config GENERIC_HARDIRQS
1242 config GENERIC_IRQ_PROBE
1248 depends on SMP && !X86_VOYAGER
1253 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1256 config X86_BIOS_REBOOT
1258 depends on !(X86_VISWS || X86_VOYAGER)
1261 config X86_TRAMPOLINE
1263 depends on X86_SMP || (X86_VOYAGER && SMP)
1268 depends on X86 && !EMBEDDED
projects / linux-2.6 / blob