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 - "Winchip-C6" for original IDT Winchip.
183 - "Winchip-2" for IDT Winchip 2.
184 - "Winchip-2A" for IDT Winchips with 3dNow! capabilities.
185 - "CyrixIII/VIA C3" for VIA Cyrix III or VIA C3.
186 - "VIA C3-2 for VIA C3-2 "Nehemiah" (model 9 and above).
188 If you don't know what to do, choose "386".
193 Select this for a 486 series processor, either Intel or one of the
194 compatible processors from AMD, Cyrix, IBM, or Intel. Includes DX,
195 DX2, and DX4 variants; also SL/SLC/SLC2/SLC3/SX/SX2 and UMC U5D or
199 bool "586/K5/5x86/6x86/6x86MX"
201 Select this for an 586 or 686 series processor such as the AMD K5,
202 the Intel 5x86 or 6x86, or the Intel 6x86MX. This choice does not
203 assume the RDTSC (Read Time Stamp Counter) instruction.
206 bool "Pentium-Classic"
208 Select this for a Pentium Classic processor with the RDTSC (Read
209 Time Stamp Counter) instruction for benchmarking.
214 Select this for a Pentium with the MMX graphics/multimedia
215 extended instructions.
220 Select this for Intel Pentium Pro chips. This enables the use of
221 Pentium Pro extended instructions, and disables the init-time guard
222 against the f00f bug found in earlier Pentiums.
225 bool "Pentium-II/Celeron(pre-Coppermine)"
227 Select this for Intel chips based on the Pentium-II and
228 pre-Coppermine Celeron core. This option enables an unaligned
229 copy optimization, compiles the kernel with optimization flags
230 tailored for the chip, and applies any applicable Pentium Pro
234 bool "Pentium-III/Celeron(Coppermine)/Pentium-III Xeon"
236 Select this for Intel chips based on the Pentium-III and
237 Celeron-Coppermine core. This option enables use of some
238 extended prefetch instructions in addition to the Pentium II
244 Select this for Intel Pentium M (not Pentium-4 M)
248 bool "Pentium-4/Celeron(P4-based)/Pentium-4 M/Xeon"
250 Select this for Intel Pentium 4 chips. This includes the
251 Pentium 4, P4-based Celeron and Xeon, and Pentium-4 M
252 (not Pentium M) chips. This option enables compile flags
253 optimized for the chip, uses the correct cache shift, and
254 applies any applicable Pentium III optimizations.
257 bool "K6/K6-II/K6-III"
259 Select this for an AMD K6-family processor. Enables use of
260 some extended instructions, and passes appropriate optimization
264 bool "Athlon/Duron/K7"
266 Select this for an AMD Athlon K7-family processor. Enables use of
267 some extended instructions, and passes appropriate optimization
271 bool "Opteron/Athlon64/Hammer/K8"
273 Select this for an AMD Opteron or Athlon64 Hammer-family processor. Enables
274 use of some extended instructions, and passes appropriate optimization
280 Select this for a Transmeta Crusoe processor. Treats the processor
281 like a 586 with TSC, and sets some GCC optimization flags (like a
282 Pentium Pro with no alignment requirements).
287 Select this for an IDT Winchip C6 chip. Linux and GCC
288 treat this chip as a 586TSC with some extended instructions
289 and alignment requirements.
294 Select this for an IDT Winchip-2. Linux and GCC
295 treat this chip as a 586TSC with some extended instructions
296 and alignment requirements.
299 bool "Winchip-2A/Winchip-3"
301 Select this for an IDT Winchip-2A or 3. Linux and GCC
302 treat this chip as a 586TSC with some extended instructions
303 and alignment reqirements. Also enable out of order memory
304 stores for this CPU, which can increase performance of some
308 bool "CyrixIII/VIA-C3"
310 Select this for a Cyrix III or C3 chip. Presently Linux and GCC
311 treat this chip as a generic 586. Whilst the CPU is 686 class,
312 it lacks the cmov extension which gcc assumes is present when
314 Note that Nehemiah (Model 9) and above will not boot with this
315 kernel due to them lacking the 3DNow! instructions used in earlier
316 incarnations of the CPU.
319 bool "VIA C3-2 (Nehemiah)"
321 Select this for a VIA C3 "Nehemiah". Selecting this enables usage
322 of SSE and tells gcc to treat the CPU as a 686.
323 Note, this kernel will not boot on older (pre model 9) C3s.
328 bool "Generic x86 support"
330 Instead of just including optimizations for the selected
331 x86 variant (e.g. PII, Crusoe or Athlon), include some more
332 generic optimizations as well. This will make the kernel
333 perform better on x86 CPUs other than that selected.
335 This is really intended for distributors who need more
336 generic optimizations.
341 # Define implied options from the CPU selection here
353 config X86_L1_CACHE_SHIFT
355 default "7" if MPENTIUM4 || X86_GENERIC
356 default "4" if X86_ELAN || M486 || M386
357 default "5" if MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCRUSOE || MCYRIXIII || MK6 || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || M586 || MVIAC3_2
358 default "6" if MK7 || MK8 || MPENTIUMM
360 config RWSEM_GENERIC_SPINLOCK
365 config RWSEM_XCHGADD_ALGORITHM
370 config X86_PPRO_FENCE
372 depends on M686 || M586MMX || M586TSC || M586 || M486 || M386
377 depends on M586MMX || M586TSC || M586 || M486 || M386
380 config X86_WP_WORKS_OK
400 config X86_ALIGNMENT_16
402 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || X86_ELAN || MK6 || M586MMX || M586TSC || M586 || M486 || MVIAC3_2
407 depends on MK7 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || MK8
410 config X86_INTEL_USERCOPY
412 depends on MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M586MMX || X86_GENERIC || MK8 || MK7
415 config X86_USE_PPRO_CHECKSUM
417 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC3_2
422 depends on MCYRIXIII || MK7
427 depends on (MWINCHIP3D || MWINCHIP2 || MWINCHIPC6) && MTRR
431 bool "HPET Timer Support"
433 This enables the use of the HPET for the kernel's internal timer.
434 HPET is the next generation timer replacing legacy 8254s.
435 You can safely choose Y here. However, HPET will only be
436 activated if the platform and the BIOS support this feature.
437 Otherwise the 8254 will be used for timing services.
439 Choose N to continue using the legacy 8254 timer.
441 config HPET_EMULATE_RTC
442 bool "Provide RTC interrupt"
443 depends on HPET_TIMER && RTC=y
446 bool "Symmetric multi-processing support"
448 This enables support for systems with more than one CPU. If you have
449 a system with only one CPU, like most personal computers, say N. If
450 you have a system with more than one CPU, say Y.
452 If you say N here, the kernel will run on single and multiprocessor
453 machines, but will use only one CPU of a multiprocessor machine. If
454 you say Y here, the kernel will run on many, but not all,
455 singleprocessor machines. On a singleprocessor machine, the kernel
456 will run faster if you say N here.
458 Note that if you say Y here and choose architecture "586" or
459 "Pentium" under "Processor family", the kernel will not work on 486
460 architectures. Similarly, multiprocessor kernels for the "PPro"
461 architecture may not work on all Pentium based boards.
463 People using multiprocessor machines who say Y here should also say
464 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
465 Management" code will be disabled if you say Y here.
467 See also the <file:Documentation/smp.txt>,
468 <file:Documentation/i386/IO-APIC.txt>,
469 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
470 <http://www.tldp.org/docs.html#howto>.
472 If you don't know what to do here, say N.
475 int "Maximum number of CPUs (2-255)"
478 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
481 This allows you to specify the maximum number of CPUs which this
482 kernel will support. The maximum supported value is 255 and the
483 minimum value which makes sense is 2.
485 This is purely to save memory - each supported CPU adds
486 approximately eight kilobytes to the kernel image.
489 bool "SMT (Hyperthreading) scheduler support"
493 SMT scheduler support improves the CPU scheduler's decision making
494 when dealing with Intel Pentium 4 chips with HyperThreading at a
495 cost of slightly increased overhead in some places. If unsure say
499 bool "Preemptible Kernel"
501 This option reduces the latency of the kernel when reacting to
502 real-time or interactive events by allowing a low priority process to
503 be preempted even if it is in kernel mode executing a system call.
504 This allows applications to run more reliably even when the system is
507 Say Y here if you are building a kernel for a desktop, embedded
508 or real-time system. Say N if you are unsure.
511 bool "Local APIC support on uniprocessors" if !SMP
512 depends on !(X86_VISWS || X86_VOYAGER)
514 A local APIC (Advanced Programmable Interrupt Controller) is an
515 integrated interrupt controller in the CPU. If you have a single-CPU
516 system which has a processor with a local APIC, you can say Y here to
517 enable and use it. If you say Y here even though your machine doesn't
518 have a local APIC, then the kernel will still run with no slowdown at
519 all. The local APIC supports CPU-generated self-interrupts (timer,
520 performance counters), and the NMI watchdog which detects hard
523 If you have a system with several CPUs, you do not need to say Y
524 here: the local APIC will be used automatically.
527 bool "IO-APIC support on uniprocessors"
528 depends on !SMP && X86_UP_APIC
530 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
531 SMP-capable replacement for PC-style interrupt controllers. Most
532 SMP systems and a small number of uniprocessor systems have one.
533 If you have a single-CPU system with an IO-APIC, you can say Y here
534 to use it. If you say Y here even though your machine doesn't have
535 an IO-APIC, then the kernel will still run with no slowdown at all.
537 If you have a system with several CPUs, you do not need to say Y
538 here: the IO-APIC will be used automatically.
540 config X86_LOCAL_APIC
542 depends on !SMP && X86_UP_APIC
547 depends on !SMP && X86_UP_IOAPIC
552 depends on (MWINCHIP3D || MWINCHIP2 || MCRUSOE || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2) && !X86_NUMAQ
556 bool "Machine Check Exception"
557 depends on !X86_VOYAGER
559 Machine Check Exception support allows the processor to notify the
560 kernel if it detects a problem (e.g. overheating, component failure).
561 The action the kernel takes depends on the severity of the problem,
562 ranging from a warning message on the console, to halting the machine.
563 Your processor must be a Pentium or newer to support this - check the
564 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
565 have a design flaw which leads to false MCE events - hence MCE is
566 disabled on all P5 processors, unless explicitly enabled with "mce"
567 as a boot argument. Similarly, if MCE is built in and creates a
568 problem on some new non-standard machine, you can boot with "nomce"
569 to disable it. MCE support simply ignores non-MCE processors like
570 the 386 and 486, so nearly everyone can say Y here.
572 config X86_MCE_NONFATAL
573 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
576 Enabling this feature starts a timer that triggers every 5 seconds which
577 will look at the machine check registers to see if anything happened.
578 Non-fatal problems automatically get corrected (but still logged).
579 Disable this if you don't want to see these messages.
580 Seeing the messages this option prints out may be indicative of dying hardware,
581 or out-of-spec (ie, overclocked) hardware.
582 This option only does something on certain CPUs.
583 (AMD Athlon/Duron and Intel Pentium 4)
585 config X86_MCE_P4THERMAL
586 bool "check for P4 thermal throttling interrupt."
587 depends on X86_MCE && (X86_UP_APIC || SMP)
589 Enabling this feature will cause a message to be printed when the P4
590 enters thermal throttling.
593 tristate "Toshiba Laptop support"
595 This adds a driver to safely access the System Management Mode of
596 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
597 not work on models with a Phoenix BIOS. The System Management Mode
598 is used to set the BIOS and power saving options on Toshiba portables.
600 For information on utilities to make use of this driver see the
601 Toshiba Linux utilities web site at:
602 <http://www.buzzard.org.uk/toshiba/>.
604 Say Y if you intend to run this kernel on a Toshiba portable.
608 tristate "Dell laptop support"
610 This adds a driver to safely access the System Management Mode
611 of the CPU on the Dell Inspiron 8000. The System Management Mode
612 is used to read cpu temperature and cooling fan status and to
613 control the fans on the I8K portables.
615 This driver has been tested only on the Inspiron 8000 but it may
616 also work with other Dell laptops. You can force loading on other
617 models by passing the parameter `force=1' to the module. Use at
620 For information on utilities to make use of this driver see the
621 I8K Linux utilities web site at:
622 <http://people.debian.org/~dz/i8k/>
624 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
628 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
630 If you say Y here and also to "/dev file system support" in the
631 'File systems' section, you will be able to update the microcode on
632 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
633 Pentium III, Pentium 4, Xeon etc. You will obviously need the
634 actual microcode binary data itself which is not shipped with the
637 For latest news and information on obtaining all the required
638 ingredients for this driver, check:
639 <http://www.urbanmyth.org/microcode/>.
641 To compile this driver as a module, choose M here: the
642 module will be called microcode.
645 tristate "/dev/cpu/*/msr - Model-specific register support"
647 This device gives privileged processes access to the x86
648 Model-Specific Registers (MSRs). It is a character device with
649 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
650 MSR accesses are directed to a specific CPU on multi-processor
654 tristate "/dev/cpu/*/cpuid - CPU information support"
656 This device gives processes access to the x86 CPUID instruction to
657 be executed on a specific processor. It is a character device
658 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
661 source "drivers/firmware/Kconfig"
664 prompt "High Memory Support"
670 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
671 However, the address space of 32-bit x86 processors is only 4
672 Gigabytes large. That means that, if you have a large amount of
673 physical memory, not all of it can be "permanently mapped" by the
674 kernel. The physical memory that's not permanently mapped is called
677 If you are compiling a kernel which will never run on a machine with
678 more than 1 Gigabyte total physical RAM, answer "off" here (default
679 choice and suitable for most users). This will result in a "3GB/1GB"
680 split: 3GB are mapped so that each process sees a 3GB virtual memory
681 space and the remaining part of the 4GB virtual memory space is used
682 by the kernel to permanently map as much physical memory as
685 If the machine has between 1 and 4 Gigabytes physical RAM, then
688 If more than 4 Gigabytes is used then answer "64GB" here. This
689 selection turns Intel PAE (Physical Address Extension) mode on.
690 PAE implements 3-level paging on IA32 processors. PAE is fully
691 supported by Linux, PAE mode is implemented on all recent Intel
692 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
693 then the kernel will not boot on CPUs that don't support PAE!
695 The actual amount of total physical memory will either be
696 auto detected or can be forced by using a kernel command line option
697 such as "mem=256M". (Try "man bootparam" or see the documentation of
698 your boot loader (lilo or loadlin) about how to pass options to the
699 kernel at boot time.)
701 If unsure, say "off".
706 Select this if you have a 32-bit processor and between 1 and 4
707 gigabytes of physical RAM.
712 Select this if you have a 32-bit processor and more than 4
713 gigabytes of physical RAM.
718 prompt "Memory Split User Space"
721 A different Userspace/Kernel split allows you to
722 utilize up to alsmost 3GB of RAM without the requirement
723 for HIGHMEM. It also increases the available lowmem.
726 bool "3.0GB/1.0GB Kernel (Default)"
728 This is the default split of 3GB userspace to 1GB kernel
729 space, which will result in about 860MB of lowmem.
732 bool "2.5GB/1.5GB Kernel"
734 This split provides 2.5GB userspace and 1.5GB kernel
735 space, which will result in about 1370MB of lowmem.
738 bool "2.0GB/2.0GB Kernel"
740 This split provides 2GB userspace and 2GB kernel
741 space, which will result in about 1880MB of lowmem.
744 bool "1.5GB/2.5GB Kernel"
746 This split provides 1.5GB userspace and 2.5GB kernel
747 space, which will result in about 2390MB of lowmem.
750 bool "1.0GB/3.0GB Kernel"
752 This split provides 1GB userspace and 3GB kernel
753 space, which will result in about 2900MB of lowmem.
759 depends on HIGHMEM64G || HIGHMEM4G
764 depends on HIGHMEM64G
767 # Common NUMA Features
769 bool "Numa Memory Allocation and Scheduler Support"
770 depends on SMP && HIGHMEM64G && (X86_NUMAQ || X86_GENERICARCH || (X86_SUMMIT && ACPI))
772 default y if (X86_NUMAQ || X86_SUMMIT)
774 # Need comments to help the hapless user trying to turn on NUMA support
775 comment "NUMA (NUMA-Q) requires SMP, 64GB highmem support"
776 depends on X86_NUMAQ && (!HIGHMEM64G || !SMP)
778 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
779 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
786 config HAVE_ARCH_BOOTMEM_NODE
792 bool "Allocate 3rd-level pagetables from highmem"
793 depends on HIGHMEM4G || HIGHMEM64G
795 The VM uses one page table entry for each page of physical memory.
796 For systems with a lot of RAM, this can be wasteful of precious
797 low memory. Setting this option will put user-space page table
798 entries in high memory.
800 config MATH_EMULATION
801 bool "Math emulation"
803 Linux can emulate a math coprocessor (used for floating point
804 operations) if you don't have one. 486DX and Pentium processors have
805 a math coprocessor built in, 486SX and 386 do not, unless you added
806 a 487DX or 387, respectively. (The messages during boot time can
807 give you some hints here ["man dmesg"].) Everyone needs either a
808 coprocessor or this emulation.
810 If you don't have a math coprocessor, you need to say Y here; if you
811 say Y here even though you have a coprocessor, the coprocessor will
812 be used nevertheless. (This behavior can be changed with the kernel
813 command line option "no387", which comes handy if your coprocessor
814 is broken. Try "man bootparam" or see the documentation of your boot
815 loader (lilo or loadlin) about how to pass options to the kernel at
816 boot time.) This means that it is a good idea to say Y here if you
817 intend to use this kernel on different machines.
819 More information about the internals of the Linux math coprocessor
820 emulation can be found in <file:arch/i386/math-emu/README>.
822 If you are not sure, say Y; apart from resulting in a 66 KB bigger
823 kernel, it won't hurt.
826 bool "MTRR (Memory Type Range Register) support"
828 On Intel P6 family processors (Pentium Pro, Pentium II and later)
829 the Memory Type Range Registers (MTRRs) may be used to control
830 processor access to memory ranges. This is most useful if you have
831 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
832 allows bus write transfers to be combined into a larger transfer
833 before bursting over the PCI/AGP bus. This can increase performance
834 of image write operations 2.5 times or more. Saying Y here creates a
835 /proc/mtrr file which may be used to manipulate your processor's
836 MTRRs. Typically the X server should use this.
838 This code has a reasonably generic interface so that similar
839 control registers on other processors can be easily supported
842 The Cyrix 6x86, 6x86MX and M II processors have Address Range
843 Registers (ARRs) which provide a similar functionality to MTRRs. For
844 these, the ARRs are used to emulate the MTRRs.
845 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
846 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
847 write-combining. All of these processors are supported by this code
848 and it makes sense to say Y here if you have one of them.
850 Saying Y here also fixes a problem with buggy SMP BIOSes which only
851 set the MTRRs for the boot CPU and not for the secondary CPUs. This
852 can lead to all sorts of problems, so it's good to say Y here.
854 You can safely say Y even if your machine doesn't have MTRRs, you'll
855 just add about 9 KB to your kernel.
857 See <file:Documentation/mtrr.txt> for more information.
860 bool "Boot from EFI support (EXPERIMENTAL)"
865 This enables the the kernel to boot on EFI platforms using
866 system configuration information passed to it from the firmware.
867 This also enables the kernel to use any EFI runtime services that are
868 available (such as the EFI variable services).
870 This option is only useful on systems that have EFI firmware
871 and will result in a kernel image that is ~8k larger. In addition,
872 you must use the latest ELILO loader available at
873 <http://elilo.sourceforge.net> in order to take advantage of
874 kernel initialization using EFI information (neither GRUB nor LILO know
875 anything about EFI). However, even with this option, the resultant
876 kernel should continue to boot on existing non-EFI platforms.
879 bool "Enable kernel irq balancing"
880 depends on SMP && X86_IO_APIC
883 The default yes will allow the kernel to do irq load balancing.
884 Saying no will keep the kernel from doing irq load balancing.
888 depends on (SMP || PREEMPT) && X86_CMPXCHG
891 # turning this on wastes a bunch of space.
892 # Summit needs it only when NUMA is on
895 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
899 bool "Use register arguments (EXPERIMENTAL)"
900 depends on EXPERIMENTAL
903 Compile the kernel with -mregparm=3. This uses an different ABI
904 and passes the first three arguments of a function call in registers.
905 This will probably break binary only modules.
907 This feature is only enabled for gcc-3.0 and later - earlier compilers
908 generate incorrect output with certain kernel constructs when
914 menu "Power management options (ACPI, APM)"
915 depends on !X86_VOYAGER
917 source kernel/power/Kconfig
919 source "drivers/acpi/Kconfig"
921 menu "APM (Advanced Power Management) BIOS Support"
925 tristate "APM (Advanced Power Management) BIOS support"
928 APM is a BIOS specification for saving power using several different
929 techniques. This is mostly useful for battery powered laptops with
930 APM compliant BIOSes. If you say Y here, the system time will be
931 reset after a RESUME operation, the /proc/apm device will provide
932 battery status information, and user-space programs will receive
933 notification of APM "events" (e.g. battery status change).
935 If you select "Y" here, you can disable actual use of the APM
936 BIOS by passing the "apm=off" option to the kernel at boot time.
938 Note that the APM support is almost completely disabled for
939 machines with more than one CPU.
941 In order to use APM, you will need supporting software. For location
942 and more information, read <file:Documentation/pm.txt> and the
943 Battery Powered Linux mini-HOWTO, available from
944 <http://www.tldp.org/docs.html#howto>.
946 This driver does not spin down disk drives (see the hdparm(8)
947 manpage ("man 8 hdparm") for that), and it doesn't turn off
948 VESA-compliant "green" monitors.
950 This driver does not support the TI 4000M TravelMate and the ACER
951 486/DX4/75 because they don't have compliant BIOSes. Many "green"
952 desktop machines also don't have compliant BIOSes, and this driver
953 may cause those machines to panic during the boot phase.
955 Generally, if you don't have a battery in your machine, there isn't
956 much point in using this driver and you should say N. If you get
957 random kernel OOPSes or reboots that don't seem to be related to
958 anything, try disabling/enabling this option (or disabling/enabling
961 Some other things you should try when experiencing seemingly random,
964 1) make sure that you have enough swap space and that it is
966 2) pass the "no-hlt" option to the kernel
967 3) switch on floating point emulation in the kernel and pass
968 the "no387" option to the kernel
969 4) pass the "floppy=nodma" option to the kernel
970 5) pass the "mem=4M" option to the kernel (thereby disabling
971 all but the first 4 MB of RAM)
972 6) make sure that the CPU is not over clocked.
973 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
974 8) disable the cache from your BIOS settings
975 9) install a fan for the video card or exchange video RAM
976 10) install a better fan for the CPU
977 11) exchange RAM chips
978 12) exchange the motherboard.
980 To compile this driver as a module, choose M here: the
981 module will be called apm.
983 config APM_IGNORE_USER_SUSPEND
984 bool "Ignore USER SUSPEND"
987 This option will ignore USER SUSPEND requests. On machines with a
988 compliant APM BIOS, you want to say N. However, on the NEC Versa M
989 series notebooks, it is necessary to say Y because of a BIOS bug.
992 bool "Enable PM at boot time"
995 Enable APM features at boot time. From page 36 of the APM BIOS
996 specification: "When disabled, the APM BIOS does not automatically
997 power manage devices, enter the Standby State, enter the Suspend
998 State, or take power saving steps in response to CPU Idle calls."
999 This driver will make CPU Idle calls when Linux is idle (unless this
1000 feature is turned off -- see "Do CPU IDLE calls", below). This
1001 should always save battery power, but more complicated APM features
1002 will be dependent on your BIOS implementation. You may need to turn
1003 this option off if your computer hangs at boot time when using APM
1004 support, or if it beeps continuously instead of suspending. Turn
1005 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1006 T400CDT. This is off by default since most machines do fine without
1010 bool "Make CPU Idle calls when idle"
1013 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1014 On some machines, this can activate improved power savings, such as
1015 a slowed CPU clock rate, when the machine is idle. These idle calls
1016 are made after the idle loop has run for some length of time (e.g.,
1017 333 mS). On some machines, this will cause a hang at boot time or
1018 whenever the CPU becomes idle. (On machines with more than one CPU,
1019 this option does nothing.)
1021 config APM_DISPLAY_BLANK
1022 bool "Enable console blanking using APM"
1025 Enable console blanking using the APM. Some laptops can use this to
1026 turn off the LCD backlight when the screen blanker of the Linux
1027 virtual console blanks the screen. Note that this is only used by
1028 the virtual console screen blanker, and won't turn off the backlight
1029 when using the X Window system. This also doesn't have anything to
1030 do with your VESA-compliant power-saving monitor. Further, this
1031 option doesn't work for all laptops -- it might not turn off your
1032 backlight at all, or it might print a lot of errors to the console,
1033 especially if you are using gpm.
1035 config APM_RTC_IS_GMT
1036 bool "RTC stores time in GMT"
1039 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
1040 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
1043 It is in fact recommended to store GMT in your RTC, because then you
1044 don't have to worry about daylight savings time changes. The only
1045 reason not to use GMT in your RTC is if you also run a broken OS
1046 that doesn't understand GMT.
1048 config APM_ALLOW_INTS
1049 bool "Allow interrupts during APM BIOS calls"
1052 Normally we disable external interrupts while we are making calls to
1053 the APM BIOS as a measure to lessen the effects of a badly behaving
1054 BIOS implementation. The BIOS should reenable interrupts if it
1055 needs to. Unfortunately, some BIOSes do not -- especially those in
1056 many of the newer IBM Thinkpads. If you experience hangs when you
1057 suspend, try setting this to Y. Otherwise, say N.
1059 config APM_REAL_MODE_POWER_OFF
1060 bool "Use real mode APM BIOS call to power off"
1063 Use real mode APM BIOS calls to switch off the computer. This is
1064 a work-around for a number of buggy BIOSes. Switch this option on if
1065 your computer crashes instead of powering off properly.
1069 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1073 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1075 config X86_VISWS_APIC
1077 depends on X86_VISWS
1080 config X86_LOCAL_APIC
1082 depends on (X86_VISWS || SMP) && !X86_VOYAGER
1087 depends on SMP && !(X86_VISWS || X86_VOYAGER)
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/Kconfig"
1158 depends on !(X86_VOYAGER || X86_VISWS)
1160 Find out whether you have ISA slots on your motherboard. ISA is the
1161 name of a bus system, i.e. the way the CPU talks to the other stuff
1162 inside your box. Other bus systems are PCI, EISA, MicroChannel
1163 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1164 newer boards don't support it. If you have ISA, say Y, otherwise N.
1170 The Extended Industry Standard Architecture (EISA) bus was
1171 developed as an open alternative to the IBM MicroChannel bus.
1173 The EISA bus provided some of the features of the IBM MicroChannel
1174 bus while maintaining backward compatibility with cards made for
1175 the older ISA bus. The EISA bus saw limited use between 1988 and
1176 1995 when it was made obsolete by the PCI bus.
1178 Say Y here if you are building a kernel for an EISA-based machine.
1182 source "drivers/eisa/Kconfig"
1186 depends on !(X86_VISWS || X86_VOYAGER)
1188 MicroChannel Architecture is found in some IBM PS/2 machines and
1189 laptops. It is a bus system similar to PCI or ISA. See
1190 <file:Documentation/mca.txt> (and especially the web page given
1191 there) before attempting to build an MCA bus kernel.
1194 depends on X86_VOYAGER
1195 default y if X86_VOYAGER
1197 source "drivers/mca/Kconfig"
1200 tristate "NatSemi SCx200 support"
1201 depends on !X86_VOYAGER
1203 This provides basic support for the National Semiconductor SCx200
1204 processor. Right now this is just a driver for the GPIO pins.
1206 If you don't know what to do here, say N.
1208 This support is also available as a module. If compiled as a
1209 module, it will be called scx200.
1211 source "drivers/pcmcia/Kconfig"
1213 source "drivers/pci/hotplug/Kconfig"
1217 menu "Executable file formats"
1219 source "fs/Kconfig.binfmt"
1223 source "drivers/Kconfig"
1227 source "arch/i386/oprofile/Kconfig"
1229 source "arch/i386/Kconfig.debug"
1231 source "kernel/vserver/Kconfig"
1233 source "security/Kconfig"
1235 source "crypto/Kconfig"
1237 source "lib/Kconfig"
1241 depends on SMP && !X86_VOYAGER
1246 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1249 config X86_BIOS_REBOOT
1251 depends on !(X86_VISWS || X86_VOYAGER)
1254 config X86_TRAMPOLINE
1256 depends on X86_SMP || (X86_VOYAGER && SMP)
1261 depends on X86 && !EMBEDDED