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 Cyrix 5x86, 6x86 and 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.
510 config PREEMPT_VOLUNTARY
511 bool "Voluntary Kernel Preemption"
515 This option reduces the latency of the kernel by adding more
516 "explicit preemption points" to the kernel code. These new
517 preemption points have been selected to minimize the maximum
518 latency of rescheduling, providing faster application reactions.
520 Say Y here if you are building a kernel for a desktop system.
521 Say N if you are unsure.
524 bool "Local APIC support on uniprocessors" if !SMP
525 depends on !(X86_VISWS || X86_VOYAGER)
527 A local APIC (Advanced Programmable Interrupt Controller) is an
528 integrated interrupt controller in the CPU. If you have a single-CPU
529 system which has a processor with a local APIC, you can say Y here to
530 enable and use it. If you say Y here even though your machine doesn't
531 have a local APIC, then the kernel will still run with no slowdown at
532 all. The local APIC supports CPU-generated self-interrupts (timer,
533 performance counters), and the NMI watchdog which detects hard
536 If you have a system with several CPUs, you do not need to say Y
537 here: the local APIC will be used automatically.
540 bool "IO-APIC support on uniprocessors"
541 depends on !SMP && X86_UP_APIC
543 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
544 SMP-capable replacement for PC-style interrupt controllers. Most
545 SMP systems and a small number of uniprocessor systems have one.
546 If you have a single-CPU system with an IO-APIC, you can say Y here
547 to use it. If you say Y here even though your machine doesn't have
548 an IO-APIC, then the kernel will still run with no slowdown at all.
550 If you have a system with several CPUs, you do not need to say Y
551 here: the IO-APIC will be used automatically.
553 config X86_LOCAL_APIC
555 depends on !SMP && X86_UP_APIC
560 depends on !SMP && X86_UP_IOAPIC
565 depends on (MWINCHIP3D || MWINCHIP2 || MCRUSOE || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2) && !X86_NUMAQ
569 bool "Machine Check Exception"
570 depends on !X86_VOYAGER
572 Machine Check Exception support allows the processor to notify the
573 kernel if it detects a problem (e.g. overheating, component failure).
574 The action the kernel takes depends on the severity of the problem,
575 ranging from a warning message on the console, to halting the machine.
576 Your processor must be a Pentium or newer to support this - check the
577 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
578 have a design flaw which leads to false MCE events - hence MCE is
579 disabled on all P5 processors, unless explicitly enabled with "mce"
580 as a boot argument. Similarly, if MCE is built in and creates a
581 problem on some new non-standard machine, you can boot with "nomce"
582 to disable it. MCE support simply ignores non-MCE processors like
583 the 386 and 486, so nearly everyone can say Y here.
585 config X86_MCE_NONFATAL
586 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
589 Enabling this feature starts a timer that triggers every 5 seconds which
590 will look at the machine check registers to see if anything happened.
591 Non-fatal problems automatically get corrected (but still logged).
592 Disable this if you don't want to see these messages.
593 Seeing the messages this option prints out may be indicative of dying hardware,
594 or out-of-spec (ie, overclocked) hardware.
595 This option only does something on certain CPUs.
596 (AMD Athlon/Duron and Intel Pentium 4)
598 config X86_MCE_P4THERMAL
599 bool "check for P4 thermal throttling interrupt."
600 depends on X86_MCE && (X86_UP_APIC || SMP)
602 Enabling this feature will cause a message to be printed when the P4
603 enters thermal throttling.
606 tristate "Toshiba Laptop support"
608 This adds a driver to safely access the System Management Mode of
609 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
610 not work on models with a Phoenix BIOS. The System Management Mode
611 is used to set the BIOS and power saving options on Toshiba portables.
613 For information on utilities to make use of this driver see the
614 Toshiba Linux utilities web site at:
615 <http://www.buzzard.org.uk/toshiba/>.
617 Say Y if you intend to run this kernel on a Toshiba portable.
621 tristate "Dell laptop support"
623 This adds a driver to safely access the System Management Mode
624 of the CPU on the Dell Inspiron 8000. The System Management Mode
625 is used to read cpu temperature and cooling fan status and to
626 control the fans on the I8K portables.
628 This driver has been tested only on the Inspiron 8000 but it may
629 also work with other Dell laptops. You can force loading on other
630 models by passing the parameter `force=1' to the module. Use at
633 For information on utilities to make use of this driver see the
634 I8K Linux utilities web site at:
635 <http://people.debian.org/~dz/i8k/>
637 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
641 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
643 If you say Y here and also to "/dev file system support" in the
644 'File systems' section, you will be able to update the microcode on
645 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
646 Pentium III, Pentium 4, Xeon etc. You will obviously need the
647 actual microcode binary data itself which is not shipped with the
650 For latest news and information on obtaining all the required
651 ingredients for this driver, check:
652 <http://www.urbanmyth.org/microcode/>.
654 To compile this driver as a module, choose M here: the
655 module will be called microcode.
658 tristate "/dev/cpu/*/msr - Model-specific register support"
660 This device gives privileged processes access to the x86
661 Model-Specific Registers (MSRs). It is a character device with
662 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
663 MSR accesses are directed to a specific CPU on multi-processor
667 tristate "/dev/cpu/*/cpuid - CPU information support"
669 This device gives processes access to the x86 CPUID instruction to
670 be executed on a specific processor. It is a character device
671 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
674 source "drivers/firmware/Kconfig"
677 prompt "High Memory Support"
683 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
684 However, the address space of 32-bit x86 processors is only 4
685 Gigabytes large. That means that, if you have a large amount of
686 physical memory, not all of it can be "permanently mapped" by the
687 kernel. The physical memory that's not permanently mapped is called
690 If you are compiling a kernel which will never run on a machine with
691 more than 1 Gigabyte total physical RAM, answer "off" here (default
692 choice and suitable for most users). This will result in a "3GB/1GB"
693 split: 3GB are mapped so that each process sees a 3GB virtual memory
694 space and the remaining part of the 4GB virtual memory space is used
695 by the kernel to permanently map as much physical memory as
698 If the machine has between 1 and 4 Gigabytes physical RAM, then
701 If more than 4 Gigabytes is used then answer "64GB" here. This
702 selection turns Intel PAE (Physical Address Extension) mode on.
703 PAE implements 3-level paging on IA32 processors. PAE is fully
704 supported by Linux, PAE mode is implemented on all recent Intel
705 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
706 then the kernel will not boot on CPUs that don't support PAE!
708 The actual amount of total physical memory will either be
709 auto detected or can be forced by using a kernel command line option
710 such as "mem=256M". (Try "man bootparam" or see the documentation of
711 your boot loader (lilo or loadlin) about how to pass options to the
712 kernel at boot time.)
714 If unsure, say "off".
719 Select this if you have a 32-bit processor and between 1 and 4
720 gigabytes of physical RAM.
725 Select this if you have a 32-bit processor and more than 4
726 gigabytes of physical RAM.
731 prompt "Memory Split User Space"
734 A different Userspace/Kernel split allows you to
735 utilize up to alsmost 3GB of RAM without the requirement
736 for HIGHMEM. It also increases the available lowmem.
739 bool "3.0GB/1.0GB Kernel (Default)"
741 This is the default split of 3GB userspace to 1GB kernel
742 space, which will result in about 860MB of lowmem.
745 bool "2.5GB/1.5GB Kernel"
747 This split provides 2.5GB userspace and 1.5GB kernel
748 space, which will result in about 1370MB of lowmem.
751 bool "2.0GB/2.0GB Kernel"
753 This split provides 2GB userspace and 2GB kernel
754 space, which will result in about 1880MB of lowmem.
757 bool "1.5GB/2.5GB Kernel"
759 This split provides 1.5GB userspace and 2.5GB kernel
760 space, which will result in about 2390MB of lowmem.
763 bool "1.0GB/3.0GB Kernel"
765 This split provides 1GB userspace and 3GB kernel
766 space, which will result in about 2900MB of lowmem.
772 depends on HIGHMEM64G || HIGHMEM4G
777 depends on HIGHMEM64G
780 # Common NUMA Features
782 bool "Numa Memory Allocation and Scheduler Support"
783 depends on SMP && HIGHMEM64G && (X86_NUMAQ || X86_GENERICARCH || (X86_SUMMIT && ACPI))
785 default y if (X86_NUMAQ || X86_SUMMIT)
787 # Need comments to help the hapless user trying to turn on NUMA support
788 comment "NUMA (NUMA-Q) requires SMP, 64GB highmem support"
789 depends on X86_NUMAQ && (!HIGHMEM64G || !SMP)
791 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
792 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
799 config HAVE_ARCH_BOOTMEM_NODE
805 bool "Allocate 3rd-level pagetables from highmem"
806 depends on HIGHMEM4G || HIGHMEM64G
808 The VM uses one page table entry for each page of physical memory.
809 For systems with a lot of RAM, this can be wasteful of precious
810 low memory. Setting this option will put user-space page table
811 entries in high memory.
813 config MATH_EMULATION
814 bool "Math emulation"
816 Linux can emulate a math coprocessor (used for floating point
817 operations) if you don't have one. 486DX and Pentium processors have
818 a math coprocessor built in, 486SX and 386 do not, unless you added
819 a 487DX or 387, respectively. (The messages during boot time can
820 give you some hints here ["man dmesg"].) Everyone needs either a
821 coprocessor or this emulation.
823 If you don't have a math coprocessor, you need to say Y here; if you
824 say Y here even though you have a coprocessor, the coprocessor will
825 be used nevertheless. (This behavior can be changed with the kernel
826 command line option "no387", which comes handy if your coprocessor
827 is broken. Try "man bootparam" or see the documentation of your boot
828 loader (lilo or loadlin) about how to pass options to the kernel at
829 boot time.) This means that it is a good idea to say Y here if you
830 intend to use this kernel on different machines.
832 More information about the internals of the Linux math coprocessor
833 emulation can be found in <file:arch/i386/math-emu/README>.
835 If you are not sure, say Y; apart from resulting in a 66 KB bigger
836 kernel, it won't hurt.
839 bool "MTRR (Memory Type Range Register) support"
841 On Intel P6 family processors (Pentium Pro, Pentium II and later)
842 the Memory Type Range Registers (MTRRs) may be used to control
843 processor access to memory ranges. This is most useful if you have
844 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
845 allows bus write transfers to be combined into a larger transfer
846 before bursting over the PCI/AGP bus. This can increase performance
847 of image write operations 2.5 times or more. Saying Y here creates a
848 /proc/mtrr file which may be used to manipulate your processor's
849 MTRRs. Typically the X server should use this.
851 This code has a reasonably generic interface so that similar
852 control registers on other processors can be easily supported
855 The Cyrix 6x86, 6x86MX and M II processors have Address Range
856 Registers (ARRs) which provide a similar functionality to MTRRs. For
857 these, the ARRs are used to emulate the MTRRs.
858 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
859 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
860 write-combining. All of these processors are supported by this code
861 and it makes sense to say Y here if you have one of them.
863 Saying Y here also fixes a problem with buggy SMP BIOSes which only
864 set the MTRRs for the boot CPU and not for the secondary CPUs. This
865 can lead to all sorts of problems, so it's good to say Y here.
867 You can safely say Y even if your machine doesn't have MTRRs, you'll
868 just add about 9 KB to your kernel.
870 See <file:Documentation/mtrr.txt> for more information.
873 bool "Boot from EFI support (EXPERIMENTAL)"
878 This enables the the kernel to boot on EFI platforms using
879 system configuration information passed to it from the firmware.
880 This also enables the kernel to use any EFI runtime services that are
881 available (such as the EFI variable services).
883 This option is only useful on systems that have EFI firmware
884 and will result in a kernel image that is ~8k larger. In addition,
885 you must use the latest ELILO loader available at
886 <http://elilo.sourceforge.net> in order to take advantage of
887 kernel initialization using EFI information (neither GRUB nor LILO know
888 anything about EFI). However, even with this option, the resultant
889 kernel should continue to boot on existing non-EFI platforms.
892 bool "Enable kernel irq balancing"
893 depends on SMP && X86_IO_APIC
896 The default yes will allow the kernel to do irq load balancing.
897 Saying no will keep the kernel from doing irq load balancing.
901 depends on (SMP || PREEMPT) && X86_CMPXCHG
904 # turning this on wastes a bunch of space.
905 # Summit needs it only when NUMA is on
908 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
912 bool "Use register arguments (EXPERIMENTAL)"
913 depends on EXPERIMENTAL
916 Compile the kernel with -mregparm=3. This uses an different ABI
917 and passes the first three arguments of a function call in registers.
918 This will probably break binary only modules.
920 This feature is only enabled for gcc-3.0 and later - earlier compilers
921 generate incorrect output with certain kernel constructs when
925 bool "kexec system call (EXPERIMENTAL)"
926 depends on EXPERIMENTAL
928 kexec is a system call that implements the ability to shutdown your
929 current kernel, and to start another kernel. It is like a reboot
930 but it is indepedent of the system firmware. And like a reboot
931 you can start any kernel with it, not just Linux.
933 The name comes from the similiarity to the exec system call.
935 It is an ongoing process to be certain the hardware in a machine
936 is properly shutdown, so do not be surprised if this code does not
937 initially work for you. It may help to enable device hotplugging
938 support. As of this writing the exact hardware interface is
939 strongly in flux, so no good recommendation can be made.
944 menu "Power management options (ACPI, APM)"
945 depends on !X86_VOYAGER
947 source kernel/power/Kconfig
949 source "drivers/acpi/Kconfig"
951 menu "APM (Advanced Power Management) BIOS Support"
955 tristate "APM (Advanced Power Management) BIOS support"
958 APM is a BIOS specification for saving power using several different
959 techniques. This is mostly useful for battery powered laptops with
960 APM compliant BIOSes. If you say Y here, the system time will be
961 reset after a RESUME operation, the /proc/apm device will provide
962 battery status information, and user-space programs will receive
963 notification of APM "events" (e.g. battery status change).
965 If you select "Y" here, you can disable actual use of the APM
966 BIOS by passing the "apm=off" option to the kernel at boot time.
968 Note that the APM support is almost completely disabled for
969 machines with more than one CPU.
971 In order to use APM, you will need supporting software. For location
972 and more information, read <file:Documentation/pm.txt> and the
973 Battery Powered Linux mini-HOWTO, available from
974 <http://www.tldp.org/docs.html#howto>.
976 This driver does not spin down disk drives (see the hdparm(8)
977 manpage ("man 8 hdparm") for that), and it doesn't turn off
978 VESA-compliant "green" monitors.
980 This driver does not support the TI 4000M TravelMate and the ACER
981 486/DX4/75 because they don't have compliant BIOSes. Many "green"
982 desktop machines also don't have compliant BIOSes, and this driver
983 may cause those machines to panic during the boot phase.
985 Generally, if you don't have a battery in your machine, there isn't
986 much point in using this driver and you should say N. If you get
987 random kernel OOPSes or reboots that don't seem to be related to
988 anything, try disabling/enabling this option (or disabling/enabling
991 Some other things you should try when experiencing seemingly random,
994 1) make sure that you have enough swap space and that it is
996 2) pass the "no-hlt" option to the kernel
997 3) switch on floating point emulation in the kernel and pass
998 the "no387" option to the kernel
999 4) pass the "floppy=nodma" option to the kernel
1000 5) pass the "mem=4M" option to the kernel (thereby disabling
1001 all but the first 4 MB of RAM)
1002 6) make sure that the CPU is not over clocked.
1003 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1004 8) disable the cache from your BIOS settings
1005 9) install a fan for the video card or exchange video RAM
1006 10) install a better fan for the CPU
1007 11) exchange RAM chips
1008 12) exchange the motherboard.
1010 To compile this driver as a module, choose M here: the
1011 module will be called apm.
1013 config APM_IGNORE_USER_SUSPEND
1014 bool "Ignore USER SUSPEND"
1017 This option will ignore USER SUSPEND requests. On machines with a
1018 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1019 series notebooks, it is necessary to say Y because of a BIOS bug.
1021 config APM_DO_ENABLE
1022 bool "Enable PM at boot time"
1025 Enable APM features at boot time. From page 36 of the APM BIOS
1026 specification: "When disabled, the APM BIOS does not automatically
1027 power manage devices, enter the Standby State, enter the Suspend
1028 State, or take power saving steps in response to CPU Idle calls."
1029 This driver will make CPU Idle calls when Linux is idle (unless this
1030 feature is turned off -- see "Do CPU IDLE calls", below). This
1031 should always save battery power, but more complicated APM features
1032 will be dependent on your BIOS implementation. You may need to turn
1033 this option off if your computer hangs at boot time when using APM
1034 support, or if it beeps continuously instead of suspending. Turn
1035 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1036 T400CDT. This is off by default since most machines do fine without
1040 bool "Make CPU Idle calls when idle"
1043 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1044 On some machines, this can activate improved power savings, such as
1045 a slowed CPU clock rate, when the machine is idle. These idle calls
1046 are made after the idle loop has run for some length of time (e.g.,
1047 333 mS). On some machines, this will cause a hang at boot time or
1048 whenever the CPU becomes idle. (On machines with more than one CPU,
1049 this option does nothing.)
1051 config APM_DISPLAY_BLANK
1052 bool "Enable console blanking using APM"
1055 Enable console blanking using the APM. Some laptops can use this to
1056 turn off the LCD backlight when the screen blanker of the Linux
1057 virtual console blanks the screen. Note that this is only used by
1058 the virtual console screen blanker, and won't turn off the backlight
1059 when using the X Window system. This also doesn't have anything to
1060 do with your VESA-compliant power-saving monitor. Further, this
1061 option doesn't work for all laptops -- it might not turn off your
1062 backlight at all, or it might print a lot of errors to the console,
1063 especially if you are using gpm.
1065 config APM_RTC_IS_GMT
1066 bool "RTC stores time in GMT"
1069 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
1070 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
1073 It is in fact recommended to store GMT in your RTC, because then you
1074 don't have to worry about daylight savings time changes. The only
1075 reason not to use GMT in your RTC is if you also run a broken OS
1076 that doesn't understand GMT.
1078 config APM_ALLOW_INTS
1079 bool "Allow interrupts during APM BIOS calls"
1082 Normally we disable external interrupts while we are making calls to
1083 the APM BIOS as a measure to lessen the effects of a badly behaving
1084 BIOS implementation. The BIOS should reenable interrupts if it
1085 needs to. Unfortunately, some BIOSes do not -- especially those in
1086 many of the newer IBM Thinkpads. If you experience hangs when you
1087 suspend, try setting this to Y. Otherwise, say N.
1089 config APM_REAL_MODE_POWER_OFF
1090 bool "Use real mode APM BIOS call to power off"
1093 Use real mode APM BIOS calls to switch off the computer. This is
1094 a work-around for a number of buggy BIOSes. Switch this option on if
1095 your computer crashes instead of powering off properly.
1099 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1103 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1105 config X86_VISWS_APIC
1107 depends on X86_VISWS
1110 config X86_LOCAL_APIC
1112 depends on (X86_VISWS || SMP) && !X86_VOYAGER
1117 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1121 bool "PCI support" if !X86_VISWS
1122 depends on !X86_VOYAGER
1123 default y if X86_VISWS
1125 Find out whether you have a PCI motherboard. PCI is the name of a
1126 bus system, i.e. the way the CPU talks to the other stuff inside
1127 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1128 VESA. If you have PCI, say Y, otherwise N.
1130 The PCI-HOWTO, available from
1131 <http://www.tldp.org/docs.html#howto>, contains valuable
1132 information about which PCI hardware does work under Linux and which
1136 prompt "PCI access mode"
1137 depends on PCI && !X86_VISWS
1140 On PCI systems, the BIOS can be used to detect the PCI devices and
1141 determine their configuration. However, some old PCI motherboards
1142 have BIOS bugs and may crash if this is done. Also, some embedded
1143 PCI-based systems don't have any BIOS at all. Linux can also try to
1144 detect the PCI hardware directly without using the BIOS.
1146 With this option, you can specify how Linux should detect the
1147 PCI devices. If you choose "BIOS", the BIOS will be used,
1148 if you choose "Direct", the BIOS won't be used, and if you
1149 choose "MMConfig", then PCI Express MMCONFIG will be used.
1150 If you choose "Any", the kernel will try MMCONFIG, then the
1151 direct access method and falls back to the BIOS if that doesn't
1152 work. If unsure, go with the default, which is "Any".
1157 config PCI_GOMMCONFIG
1170 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1175 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1180 depends on PCI && (PCI_GOMMCONFIG || (PCI_GOANY && ACPI))
1184 source "drivers/pci/Kconfig"
1188 depends on !(X86_VOYAGER || X86_VISWS)
1190 Find out whether you have ISA slots on your motherboard. ISA is the
1191 name of a bus system, i.e. the way the CPU talks to the other stuff
1192 inside your box. Other bus systems are PCI, EISA, MicroChannel
1193 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1194 newer boards don't support it. If you have ISA, say Y, otherwise N.
1200 The Extended Industry Standard Architecture (EISA) bus was
1201 developed as an open alternative to the IBM MicroChannel bus.
1203 The EISA bus provided some of the features of the IBM MicroChannel
1204 bus while maintaining backward compatibility with cards made for
1205 the older ISA bus. The EISA bus saw limited use between 1988 and
1206 1995 when it was made obsolete by the PCI bus.
1208 Say Y here if you are building a kernel for an EISA-based machine.
1212 source "drivers/eisa/Kconfig"
1216 depends on !(X86_VISWS || X86_VOYAGER)
1218 MicroChannel Architecture is found in some IBM PS/2 machines and
1219 laptops. It is a bus system similar to PCI or ISA. See
1220 <file:Documentation/mca.txt> (and especially the web page given
1221 there) before attempting to build an MCA bus kernel.
1224 depends on X86_VOYAGER
1225 default y if X86_VOYAGER
1227 source "drivers/mca/Kconfig"
1230 tristate "NatSemi SCx200 support"
1231 depends on !X86_VOYAGER
1233 This provides basic support for the National Semiconductor SCx200
1234 processor. Right now this is just a driver for the GPIO pins.
1236 If you don't know what to do here, say N.
1238 This support is also available as a module. If compiled as a
1239 module, it will be called scx200.
1241 source "drivers/pcmcia/Kconfig"
1243 source "drivers/pci/hotplug/Kconfig"
1247 menu "Executable file formats"
1249 source "fs/Kconfig.binfmt"
1253 source "drivers/Kconfig"
1257 source "arch/i386/oprofile/Kconfig"
1259 source "arch/i386/Kconfig.debug"
1261 source "kernel/vserver/Kconfig"
1263 source "security/Kconfig"
1265 source "crypto/Kconfig"
1267 source "lib/Kconfig"
1271 depends on SMP && !X86_VOYAGER
1276 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1279 config X86_BIOS_REBOOT
1281 depends on !(X86_VISWS || X86_VOYAGER)
1284 config X86_TRAMPOLINE
1286 depends on X86_SMP || (X86_VOYAGER && SMP)
1291 depends on X86 && !EMBEDDED