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.
17 config SEMAPHORE_SLEEPERS
32 config GENERIC_ISA_DMA
40 config GENERIC_HWEIGHT
44 config ARCH_MAY_HAVE_PC_FDC
54 menu "Processor type and features"
57 bool "Symmetric multi-processing support"
59 This enables support for systems with more than one CPU. If you have
60 a system with only one CPU, like most personal computers, say N. If
61 you have a system with more than one CPU, say Y.
63 If you say N here, the kernel will run on single and multiprocessor
64 machines, but will use only one CPU of a multiprocessor machine. If
65 you say Y here, the kernel will run on many, but not all,
66 singleprocessor machines. On a singleprocessor machine, the kernel
67 will run faster if you say N here.
69 Note that if you say Y here and choose architecture "586" or
70 "Pentium" under "Processor family", the kernel will not work on 486
71 architectures. Similarly, multiprocessor kernels for the "PPro"
72 architecture may not work on all Pentium based boards.
74 People using multiprocessor machines who say Y here should also say
75 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
76 Management" code will be disabled if you say Y here.
78 See also the <file:Documentation/smp.txt>,
79 <file:Documentation/i386/IO-APIC.txt>,
80 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
81 <http://www.tldp.org/docs.html#howto>.
83 If you don't know what to do here, say N.
86 prompt "Subarchitecture Type"
92 Choose this option if your computer is a standard PC or compatible.
96 select X86_UP_APIC if !SMP && XEN_PRIVILEGED_GUEST
97 select X86_UP_IOAPIC if !SMP && XEN_PRIVILEGED_GUEST
100 Choose this option if you plan to run this kernel on top of the
106 Select this for an AMD Elan processor.
108 Do not use this option for K6/Athlon/Opteron processors!
110 If unsure, choose "PC-compatible" instead.
115 Voyager is an MCA-based 32-way capable SMP architecture proprietary
116 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
120 If you do not specifically know you have a Voyager based machine,
121 say N here, otherwise the kernel you build will not be bootable.
124 bool "NUMAQ (IBM/Sequent)"
128 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
129 multiquad box. This changes the way that processors are bootstrapped,
130 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
131 You will need a new lynxer.elf file to flash your firmware with - send
132 email to <Martin.Bligh@us.ibm.com>.
135 bool "Summit/EXA (IBM x440)"
138 This option is needed for IBM systems that use the Summit/EXA chipset.
139 In particular, it is needed for the x440.
141 If you don't have one of these computers, you should say N here.
144 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
147 This option is needed for the systems that have more than 8 CPUs
148 and if the system is not of any sub-arch type above.
150 If you don't have such a system, you should say N here.
153 bool "SGI 320/540 (Visual Workstation)"
155 The SGI Visual Workstation series is an IA32-based workstation
156 based on SGI systems chips with some legacy PC hardware attached.
158 Say Y here to create a kernel to run on the SGI 320 or 540.
160 A kernel compiled for the Visual Workstation will not run on PCs
161 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
163 config X86_GENERICARCH
164 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
167 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
168 It is intended for a generic binary kernel.
171 bool "Support for Unisys ES7000 IA32 series"
174 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
175 supposed to run on an IA32-based Unisys ES7000 system.
176 Only choose this option if you have such a system, otherwise you
184 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
186 config X86_SUMMIT_NUMA
189 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
191 config X86_CYCLONE_TIMER
194 depends on X86_SUMMIT || X86_GENERICARCH
196 config ES7000_CLUSTERED_APIC
199 depends on SMP && X86_ES7000 && MPENTIUMIII
201 source "arch/i386/Kconfig.cpu"
204 bool "HPET Timer Support"
207 This enables the use of the HPET for the kernel's internal timer.
208 HPET is the next generation timer replacing legacy 8254s.
209 You can safely choose Y here. However, HPET will only be
210 activated if the platform and the BIOS support this feature.
211 Otherwise the 8254 will be used for timing services.
213 Choose N to continue using the legacy 8254 timer.
215 config HPET_EMULATE_RTC
217 depends on HPET_TIMER && RTC=y
221 int "Maximum number of CPUs (2-255)"
224 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
227 This allows you to specify the maximum number of CPUs which this
228 kernel will support. The maximum supported value is 255 and the
229 minimum value which makes sense is 2.
231 This is purely to save memory - each supported CPU adds
232 approximately eight kilobytes to the kernel image.
235 bool "SMT (Hyperthreading) scheduler support"
236 depends on SMP && !X86_XEN
239 SMT scheduler support improves the CPU scheduler's decision making
240 when dealing with Intel Pentium 4 chips with HyperThreading at a
241 cost of slightly increased overhead in some places. If unsure say
245 bool "Multi-core scheduler support"
246 depends on SMP && !X86_XEN
249 Multi-core scheduler support improves the CPU scheduler's decision
250 making when dealing with multi-core CPU chips at a cost of slightly
251 increased overhead in some places. If unsure say N here.
253 source "kernel/Kconfig.preempt"
256 bool "Local APIC support on uniprocessors"
257 depends on !SMP && !(X86_VISWS || X86_VOYAGER || XEN_UNPRIVILEGED_GUEST)
259 A local APIC (Advanced Programmable Interrupt Controller) is an
260 integrated interrupt controller in the CPU. If you have a single-CPU
261 system which has a processor with a local APIC, you can say Y here to
262 enable and use it. If you say Y here even though your machine doesn't
263 have a local APIC, then the kernel will still run with no slowdown at
264 all. The local APIC supports CPU-generated self-interrupts (timer,
265 performance counters), and the NMI watchdog which detects hard
269 bool "IO-APIC support on uniprocessors"
270 depends on X86_UP_APIC
272 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
273 SMP-capable replacement for PC-style interrupt controllers. Most
274 SMP systems and many recent uniprocessor systems have one.
276 If you have a single-CPU system with an IO-APIC, you can say Y here
277 to use it. If you say Y here even though your machine doesn't have
278 an IO-APIC, then the kernel will still run with no slowdown at all.
280 config X86_LOCAL_APIC
282 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !(X86_VOYAGER || XEN_UNPRIVILEGED_GUEST))
287 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER || XEN_UNPRIVILEGED_GUEST))
290 config X86_VISWS_APIC
297 depends on (MWINCHIP3D || MWINCHIP2 || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2 || MGEODEGX1) && !X86_NUMAQ && !X86_XEN
301 bool "Machine Check Exception"
302 depends on !(X86_VOYAGER || X86_XEN)
304 Machine Check Exception support allows the processor to notify the
305 kernel if it detects a problem (e.g. overheating, component failure).
306 The action the kernel takes depends on the severity of the problem,
307 ranging from a warning message on the console, to halting the machine.
308 Your processor must be a Pentium or newer to support this - check the
309 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
310 have a design flaw which leads to false MCE events - hence MCE is
311 disabled on all P5 processors, unless explicitly enabled with "mce"
312 as a boot argument. Similarly, if MCE is built in and creates a
313 problem on some new non-standard machine, you can boot with "nomce"
314 to disable it. MCE support simply ignores non-MCE processors like
315 the 386 and 486, so nearly everyone can say Y here.
317 config X86_MCE_NONFATAL
318 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
321 Enabling this feature starts a timer that triggers every 5 seconds which
322 will look at the machine check registers to see if anything happened.
323 Non-fatal problems automatically get corrected (but still logged).
324 Disable this if you don't want to see these messages.
325 Seeing the messages this option prints out may be indicative of dying hardware,
326 or out-of-spec (ie, overclocked) hardware.
327 This option only does something on certain CPUs.
328 (AMD Athlon/Duron and Intel Pentium 4)
330 config X86_MCE_P4THERMAL
331 bool "check for P4 thermal throttling interrupt."
332 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
334 Enabling this feature will cause a message to be printed when the P4
335 enters thermal throttling.
338 tristate "Toshiba Laptop support"
340 This adds a driver to safely access the System Management Mode of
341 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
342 not work on models with a Phoenix BIOS. The System Management Mode
343 is used to set the BIOS and power saving options on Toshiba portables.
345 For information on utilities to make use of this driver see the
346 Toshiba Linux utilities web site at:
347 <http://www.buzzard.org.uk/toshiba/>.
349 Say Y if you intend to run this kernel on a Toshiba portable.
353 tristate "Dell laptop support"
355 This adds a driver to safely access the System Management Mode
356 of the CPU on the Dell Inspiron 8000. The System Management Mode
357 is used to read cpu temperature and cooling fan status and to
358 control the fans on the I8K portables.
360 This driver has been tested only on the Inspiron 8000 but it may
361 also work with other Dell laptops. You can force loading on other
362 models by passing the parameter `force=1' to the module. Use at
365 For information on utilities to make use of this driver see the
366 I8K Linux utilities web site at:
367 <http://people.debian.org/~dz/i8k/>
369 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
372 config X86_REBOOTFIXUPS
373 bool "Enable X86 board specific fixups for reboot"
377 This enables chipset and/or board specific fixups to be done
378 in order to get reboot to work correctly. This is only needed on
379 some combinations of hardware and BIOS. The symptom, for which
380 this config is intended, is when reboot ends with a stalled/hung
383 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
386 Say Y if you want to enable the fixup. Currently, it's safe to
387 enable this option even if you don't need it.
391 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
392 depends on !XEN_UNPRIVILEGED_GUEST
394 If you say Y here and also to "/dev file system support" in the
395 'File systems' section, you will be able to update the microcode on
396 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
397 Pentium III, Pentium 4, Xeon etc. You will obviously need the
398 actual microcode binary data itself which is not shipped with the
401 For latest news and information on obtaining all the required
402 ingredients for this driver, check:
403 <http://www.urbanmyth.org/microcode/>.
405 To compile this driver as a module, choose M here: the
406 module will be called microcode.
409 tristate "/dev/cpu/*/msr - Model-specific register support"
412 This device gives privileged processes access to the x86
413 Model-Specific Registers (MSRs). It is a character device with
414 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
415 MSR accesses are directed to a specific CPU on multi-processor
419 tristate "/dev/cpu/*/cpuid - CPU information support"
421 This device gives processes access to the x86 CPUID instruction to
422 be executed on a specific processor. It is a character device
423 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
430 source "drivers/firmware/Kconfig"
433 prompt "High Memory Support"
438 depends on !X86_NUMAQ
440 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
441 However, the address space of 32-bit x86 processors is only 4
442 Gigabytes large. That means that, if you have a large amount of
443 physical memory, not all of it can be "permanently mapped" by the
444 kernel. The physical memory that's not permanently mapped is called
447 If you are compiling a kernel which will never run on a machine with
448 more than 1 Gigabyte total physical RAM, answer "off" here (default
449 choice and suitable for most users). This will result in a "3GB/1GB"
450 split: 3GB are mapped so that each process sees a 3GB virtual memory
451 space and the remaining part of the 4GB virtual memory space is used
452 by the kernel to permanently map as much physical memory as
455 If the machine has between 1 and 4 Gigabytes physical RAM, then
458 If more than 4 Gigabytes is used then answer "64GB" here. This
459 selection turns Intel PAE (Physical Address Extension) mode on.
460 PAE implements 3-level paging on IA32 processors. PAE is fully
461 supported by Linux, PAE mode is implemented on all recent Intel
462 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
463 then the kernel will not boot on CPUs that don't support PAE!
465 The actual amount of total physical memory will either be
466 auto detected or can be forced by using a kernel command line option
467 such as "mem=256M". (Try "man bootparam" or see the documentation of
468 your boot loader (lilo or loadlin) about how to pass options to the
469 kernel at boot time.)
471 If unsure, say "off".
475 depends on !X86_NUMAQ
477 Select this if you have a 32-bit processor and between 1 and 4
478 gigabytes of physical RAM.
482 depends on X86_CMPXCHG64
484 Select this if you have a 32-bit processor and more than 4
485 gigabytes of physical RAM.
490 depends on EXPERIMENTAL && !X86_PAE
491 prompt "Memory split" if EMBEDDED
494 Select the desired split between kernel and user memory.
496 If the address range available to the kernel is less than the
497 physical memory installed, the remaining memory will be available
498 as "high memory". Accessing high memory is a little more costly
499 than low memory, as it needs to be mapped into the kernel first.
500 Note that increasing the kernel address space limits the range
501 available to user programs, making the address space there
502 tighter. Selecting anything other than the default 3G/1G split
503 will also likely make your kernel incompatible with binary-only
506 If you are not absolutely sure what you are doing, leave this
510 bool "3G/1G user/kernel split"
511 config VMSPLIT_3G_OPT
512 bool "3G/1G user/kernel split (for full 1G low memory)"
514 bool "2G/2G user/kernel split"
516 bool "1G/3G user/kernel split"
521 default 0xB0000000 if VMSPLIT_3G_OPT
522 default 0x78000000 if VMSPLIT_2G
523 default 0x40000000 if VMSPLIT_1G
528 depends on HIGHMEM64G || HIGHMEM4G
533 depends on HIGHMEM64G
536 # Common NUMA Features
538 bool "Numa Memory Allocation and Scheduler Support"
539 depends on SMP && HIGHMEM64G && (X86_NUMAQ || X86_GENERICARCH || (X86_SUMMIT && ACPI))
541 default y if (X86_NUMAQ || X86_SUMMIT)
543 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
544 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
548 default "4" if X86_NUMAQ
550 depends on NEED_MULTIPLE_NODES
552 config HAVE_ARCH_BOOTMEM_NODE
557 config ARCH_HAVE_MEMORY_PRESENT
559 depends on DISCONTIGMEM
562 config NEED_NODE_MEMMAP_SIZE
564 depends on DISCONTIGMEM || SPARSEMEM
567 config HAVE_ARCH_ALLOC_REMAP
572 config ARCH_FLATMEM_ENABLE
574 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
576 config ARCH_DISCONTIGMEM_ENABLE
580 config ARCH_DISCONTIGMEM_DEFAULT
584 config ARCH_SPARSEMEM_ENABLE
586 depends on (NUMA || (X86_PC && EXPERIMENTAL))
587 select SPARSEMEM_STATIC
589 config ARCH_SELECT_MEMORY_MODEL
591 depends on ARCH_SPARSEMEM_ENABLE
595 config HAVE_ARCH_EARLY_PFN_TO_NID
601 bool "Allocate 3rd-level pagetables from highmem"
602 depends on (HIGHMEM4G || HIGHMEM64G) && !X86_XEN
604 The VM uses one page table entry for each page of physical memory.
605 For systems with a lot of RAM, this can be wasteful of precious
606 low memory. Setting this option will put user-space page table
607 entries in high memory.
609 config MATH_EMULATION
610 bool "Math emulation"
613 Linux can emulate a math coprocessor (used for floating point
614 operations) if you don't have one. 486DX and Pentium processors have
615 a math coprocessor built in, 486SX and 386 do not, unless you added
616 a 487DX or 387, respectively. (The messages during boot time can
617 give you some hints here ["man dmesg"].) Everyone needs either a
618 coprocessor or this emulation.
620 If you don't have a math coprocessor, you need to say Y here; if you
621 say Y here even though you have a coprocessor, the coprocessor will
622 be used nevertheless. (This behavior can be changed with the kernel
623 command line option "no387", which comes handy if your coprocessor
624 is broken. Try "man bootparam" or see the documentation of your boot
625 loader (lilo or loadlin) about how to pass options to the kernel at
626 boot time.) This means that it is a good idea to say Y here if you
627 intend to use this kernel on different machines.
629 More information about the internals of the Linux math coprocessor
630 emulation can be found in <file:arch/i386/math-emu/README>.
632 If you are not sure, say Y; apart from resulting in a 66 KB bigger
633 kernel, it won't hurt.
636 bool "MTRR (Memory Type Range Register) support"
637 depends on !XEN_UNPRIVILEGED_GUEST
640 On Intel P6 family processors (Pentium Pro, Pentium II and later)
641 the Memory Type Range Registers (MTRRs) may be used to control
642 processor access to memory ranges. This is most useful if you have
643 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
644 allows bus write transfers to be combined into a larger transfer
645 before bursting over the PCI/AGP bus. This can increase performance
646 of image write operations 2.5 times or more. Saying Y here creates a
647 /proc/mtrr file which may be used to manipulate your processor's
648 MTRRs. Typically the X server should use this.
650 This code has a reasonably generic interface so that similar
651 control registers on other processors can be easily supported
654 The Cyrix 6x86, 6x86MX and M II processors have Address Range
655 Registers (ARRs) which provide a similar functionality to MTRRs. For
656 these, the ARRs are used to emulate the MTRRs.
657 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
658 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
659 write-combining. All of these processors are supported by this code
660 and it makes sense to say Y here if you have one of them.
662 Saying Y here also fixes a problem with buggy SMP BIOSes which only
663 set the MTRRs for the boot CPU and not for the secondary CPUs. This
664 can lead to all sorts of problems, so it's good to say Y here.
666 You can safely say Y even if your machine doesn't have MTRRs, you'll
667 just add about 9 KB to your kernel.
669 See <file:Documentation/mtrr.txt> for more information.
672 bool "Boot from EFI support (EXPERIMENTAL)"
673 depends on ACPI && !X86_XEN
676 This enables the the kernel to boot on EFI platforms using
677 system configuration information passed to it from the firmware.
678 This also enables the kernel to use any EFI runtime services that are
679 available (such as the EFI variable services).
681 This option is only useful on systems that have EFI firmware
682 and will result in a kernel image that is ~8k larger. In addition,
683 you must use the latest ELILO loader available at
684 <http://elilo.sourceforge.net> in order to take advantage of
685 kernel initialization using EFI information (neither GRUB nor LILO know
686 anything about EFI). However, even with this option, the resultant
687 kernel should continue to boot on existing non-EFI platforms.
690 bool "Enable kernel irq balancing"
691 depends on SMP && X86_IO_APIC && !X86_XEN
694 The default yes will allow the kernel to do irq load balancing.
695 Saying no will keep the kernel from doing irq load balancing.
697 # turning this on wastes a bunch of space.
698 # Summit needs it only when NUMA is on
701 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
705 bool "Use register arguments"
708 Compile the kernel with -mregparm=3. This instructs gcc to use
709 a more efficient function call ABI which passes the first three
710 arguments of a function call via registers, which results in denser
713 If this option is disabled, then the default ABI of passing
714 arguments via the stack is used.
719 bool "Enable seccomp to safely compute untrusted bytecode"
723 This kernel feature is useful for number crunching applications
724 that may need to compute untrusted bytecode during their
725 execution. By using pipes or other transports made available to
726 the process as file descriptors supporting the read/write
727 syscalls, it's possible to isolate those applications in
728 their own address space using seccomp. Once seccomp is
729 enabled via /proc/<pid>/seccomp, it cannot be disabled
730 and the task is only allowed to execute a few safe syscalls
731 defined by each seccomp mode.
733 If unsure, say Y. Only embedded should say N here.
735 source kernel/Kconfig.hz
738 bool "kexec system call (EXPERIMENTAL)"
739 depends on EXPERIMENTAL && !X86_XEN
741 kexec is a system call that implements the ability to shutdown your
742 current kernel, and to start another kernel. It is like a reboot
743 but it is indepedent of the system firmware. And like a reboot
744 you can start any kernel with it, not just Linux.
746 The name comes from the similiarity to the exec system call.
748 It is an ongoing process to be certain the hardware in a machine
749 is properly shutdown, so do not be surprised if this code does not
750 initially work for you. It may help to enable device hotplugging
751 support. As of this writing the exact hardware interface is
752 strongly in flux, so no good recommendation can be made.
755 bool "kernel crash dumps (EXPERIMENTAL)"
756 depends on EXPERIMENTAL
759 Generate crash dump after being started by kexec.
761 config PHYSICAL_START
762 hex "Physical address where the kernel is loaded"
764 default "0x1000000" if CRASH_DUMP
767 This gives the physical address where the kernel is loaded. Normally
768 for regular kernels this value is 0x100000 (1MB). But in the case
769 of kexec on panic the fail safe kernel needs to run at a different
770 address than the panic-ed kernel. This option is used to set the load
771 address for kernels used to capture crash dump on being kexec'ed
772 after panic. The default value for crash dump kernels is
773 0x1000000 (16MB). This can also be set based on the "X" value as
774 specified in the "crashkernel=YM@XM" command line boot parameter
775 passed to the panic-ed kernel. Typically this parameter is set as
776 crashkernel=64M@16M. Please take a look at
777 Documentation/kdump/kdump.txt for more details about crash dumps.
779 Don't change this unless you know what you are doing.
782 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
783 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
785 Say Y here to experiment with turning CPUs off and on, and to
786 enable suspend on SMP systems. CPUs can be controlled through
787 /sys/devices/system/cpu.
792 config ARCH_ENABLE_MEMORY_HOTPLUG
796 menu "Power management options (ACPI, APM)"
797 depends on !(X86_VOYAGER || XEN_UNPRIVILEGED_GUEST)
800 source kernel/power/Kconfig
803 source "drivers/acpi/Kconfig"
805 menu "APM (Advanced Power Management) BIOS Support"
806 depends on PM && !(X86_VISWS || X86_XEN)
809 tristate "APM (Advanced Power Management) BIOS support"
810 depends on PM && PM_LEGACY
812 APM is a BIOS specification for saving power using several different
813 techniques. This is mostly useful for battery powered laptops with
814 APM compliant BIOSes. If you say Y here, the system time will be
815 reset after a RESUME operation, the /proc/apm device will provide
816 battery status information, and user-space programs will receive
817 notification of APM "events" (e.g. battery status change).
819 If you select "Y" here, you can disable actual use of the APM
820 BIOS by passing the "apm=off" option to the kernel at boot time.
822 Note that the APM support is almost completely disabled for
823 machines with more than one CPU.
825 In order to use APM, you will need supporting software. For location
826 and more information, read <file:Documentation/pm.txt> and the
827 Battery Powered Linux mini-HOWTO, available from
828 <http://www.tldp.org/docs.html#howto>.
830 This driver does not spin down disk drives (see the hdparm(8)
831 manpage ("man 8 hdparm") for that), and it doesn't turn off
832 VESA-compliant "green" monitors.
834 This driver does not support the TI 4000M TravelMate and the ACER
835 486/DX4/75 because they don't have compliant BIOSes. Many "green"
836 desktop machines also don't have compliant BIOSes, and this driver
837 may cause those machines to panic during the boot phase.
839 Generally, if you don't have a battery in your machine, there isn't
840 much point in using this driver and you should say N. If you get
841 random kernel OOPSes or reboots that don't seem to be related to
842 anything, try disabling/enabling this option (or disabling/enabling
845 Some other things you should try when experiencing seemingly random,
848 1) make sure that you have enough swap space and that it is
850 2) pass the "no-hlt" option to the kernel
851 3) switch on floating point emulation in the kernel and pass
852 the "no387" option to the kernel
853 4) pass the "floppy=nodma" option to the kernel
854 5) pass the "mem=4M" option to the kernel (thereby disabling
855 all but the first 4 MB of RAM)
856 6) make sure that the CPU is not over clocked.
857 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
858 8) disable the cache from your BIOS settings
859 9) install a fan for the video card or exchange video RAM
860 10) install a better fan for the CPU
861 11) exchange RAM chips
862 12) exchange the motherboard.
864 To compile this driver as a module, choose M here: the
865 module will be called apm.
867 config APM_IGNORE_USER_SUSPEND
868 bool "Ignore USER SUSPEND"
871 This option will ignore USER SUSPEND requests. On machines with a
872 compliant APM BIOS, you want to say N. However, on the NEC Versa M
873 series notebooks, it is necessary to say Y because of a BIOS bug.
876 bool "Enable PM at boot time"
879 Enable APM features at boot time. From page 36 of the APM BIOS
880 specification: "When disabled, the APM BIOS does not automatically
881 power manage devices, enter the Standby State, enter the Suspend
882 State, or take power saving steps in response to CPU Idle calls."
883 This driver will make CPU Idle calls when Linux is idle (unless this
884 feature is turned off -- see "Do CPU IDLE calls", below). This
885 should always save battery power, but more complicated APM features
886 will be dependent on your BIOS implementation. You may need to turn
887 this option off if your computer hangs at boot time when using APM
888 support, or if it beeps continuously instead of suspending. Turn
889 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
890 T400CDT. This is off by default since most machines do fine without
894 bool "Make CPU Idle calls when idle"
897 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
898 On some machines, this can activate improved power savings, such as
899 a slowed CPU clock rate, when the machine is idle. These idle calls
900 are made after the idle loop has run for some length of time (e.g.,
901 333 mS). On some machines, this will cause a hang at boot time or
902 whenever the CPU becomes idle. (On machines with more than one CPU,
903 this option does nothing.)
905 config APM_DISPLAY_BLANK
906 bool "Enable console blanking using APM"
909 Enable console blanking using the APM. Some laptops can use this to
910 turn off the LCD backlight when the screen blanker of the Linux
911 virtual console blanks the screen. Note that this is only used by
912 the virtual console screen blanker, and won't turn off the backlight
913 when using the X Window system. This also doesn't have anything to
914 do with your VESA-compliant power-saving monitor. Further, this
915 option doesn't work for all laptops -- it might not turn off your
916 backlight at all, or it might print a lot of errors to the console,
917 especially if you are using gpm.
919 config APM_RTC_IS_GMT
920 bool "RTC stores time in GMT"
923 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
924 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
927 It is in fact recommended to store GMT in your RTC, because then you
928 don't have to worry about daylight savings time changes. The only
929 reason not to use GMT in your RTC is if you also run a broken OS
930 that doesn't understand GMT.
932 config APM_ALLOW_INTS
933 bool "Allow interrupts during APM BIOS calls"
936 Normally we disable external interrupts while we are making calls to
937 the APM BIOS as a measure to lessen the effects of a badly behaving
938 BIOS implementation. The BIOS should reenable interrupts if it
939 needs to. Unfortunately, some BIOSes do not -- especially those in
940 many of the newer IBM Thinkpads. If you experience hangs when you
941 suspend, try setting this to Y. Otherwise, say N.
943 config APM_REAL_MODE_POWER_OFF
944 bool "Use real mode APM BIOS call to power off"
947 Use real mode APM BIOS calls to switch off the computer. This is
948 a work-around for a number of buggy BIOSes. Switch this option on if
949 your computer crashes instead of powering off properly.
953 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
957 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
960 bool "PCI support" if !X86_VISWS
961 depends on !X86_VOYAGER
962 default y if X86_VISWS
964 Find out whether you have a PCI motherboard. PCI is the name of a
965 bus system, i.e. the way the CPU talks to the other stuff inside
966 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
967 VESA. If you have PCI, say Y, otherwise N.
969 The PCI-HOWTO, available from
970 <http://www.tldp.org/docs.html#howto>, contains valuable
971 information about which PCI hardware does work under Linux and which
975 prompt "PCI access mode"
976 depends on PCI && !X86_VISWS
979 On PCI systems, the BIOS can be used to detect the PCI devices and
980 determine their configuration. However, some old PCI motherboards
981 have BIOS bugs and may crash if this is done. Also, some embedded
982 PCI-based systems don't have any BIOS at all. Linux can also try to
983 detect the PCI hardware directly without using the BIOS.
985 With this option, you can specify how Linux should detect the
986 PCI devices. If you choose "BIOS", the BIOS will be used,
987 if you choose "Direct", the BIOS won't be used, and if you
988 choose "MMConfig", then PCI Express MMCONFIG will be used.
989 If you choose "Any", the kernel will try MMCONFIG, then the
990 direct access method and falls back to the BIOS if that doesn't
991 work. If unsure, go with the default, which is "Any".
997 config PCI_GOMMCONFIG
1004 bool "Xen PCI Frontend"
1007 The PCI device frontend driver allows the kernel to import arbitrary
1008 PCI devices from a PCI backend to support PCI driver domains.
1017 depends on !(X86_VISWS || X86_XEN) && PCI && (PCI_GOBIOS || PCI_GOANY)
1022 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1027 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1030 config XEN_PCIDEV_FRONTEND
1032 depends on PCI && X86_XEN && (PCI_GOXEN_FE || PCI_GOANY)
1035 config XEN_PCIDEV_FE_DEBUG
1036 bool "Xen PCI Frontend Debugging"
1037 depends on XEN_PCIDEV_FRONTEND
1040 Enables some debug statements within the PCI Frontend.
1042 source "drivers/pci/pcie/Kconfig"
1044 source "drivers/pci/Kconfig"
1052 depends on !(X86_VOYAGER || X86_VISWS || X86_XEN)
1054 Find out whether you have ISA slots on your motherboard. ISA is the
1055 name of a bus system, i.e. the way the CPU talks to the other stuff
1056 inside your box. Other bus systems are PCI, EISA, MicroChannel
1057 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1058 newer boards don't support it. If you have ISA, say Y, otherwise N.
1064 The Extended Industry Standard Architecture (EISA) bus was
1065 developed as an open alternative to the IBM MicroChannel bus.
1067 The EISA bus provided some of the features of the IBM MicroChannel
1068 bus while maintaining backward compatibility with cards made for
1069 the older ISA bus. The EISA bus saw limited use between 1988 and
1070 1995 when it was made obsolete by the PCI bus.
1072 Say Y here if you are building a kernel for an EISA-based machine.
1076 source "drivers/eisa/Kconfig"
1079 bool "MCA support" if !(X86_VISWS || X86_VOYAGER || X86_XEN)
1080 default y if X86_VOYAGER
1082 MicroChannel Architecture is found in some IBM PS/2 machines and
1083 laptops. It is a bus system similar to PCI or ISA. See
1084 <file:Documentation/mca.txt> (and especially the web page given
1085 there) before attempting to build an MCA bus kernel.
1087 source "drivers/mca/Kconfig"
1090 tristate "NatSemi SCx200 support"
1091 depends on !X86_VOYAGER
1093 This provides basic support for the National Semiconductor SCx200
1094 processor. Right now this is just a driver for the GPIO pins.
1096 If you don't know what to do here, say N.
1098 This support is also available as a module. If compiled as a
1099 module, it will be called scx200.
1101 source "drivers/pcmcia/Kconfig"
1103 source "drivers/pci/hotplug/Kconfig"
1107 menu "Executable file formats"
1109 source "fs/Kconfig.binfmt"
1113 source "net/Kconfig"
1115 source "drivers/Kconfig"
1119 menu "Instrumentation Support"
1120 depends on EXPERIMENTAL
1122 source "arch/i386/oprofile/Kconfig"
1125 bool "Kprobes (EXPERIMENTAL)"
1126 depends on EXPERIMENTAL && MODULES
1128 Kprobes allows you to trap at almost any kernel address and
1129 execute a callback function. register_kprobe() establishes
1130 a probepoint and specifies the callback. Kprobes is useful
1131 for kernel debugging, non-intrusive instrumentation and testing.
1132 If in doubt, say "N".
1135 source "arch/i386/Kconfig.debug"
1137 source "kernel/vserver/Kconfig"
1139 source "security/Kconfig"
1141 source "crypto/Kconfig"
1143 source "drivers/xen/Kconfig"
1145 source "lib/Kconfig"
1148 # Use the generic interrupt handling code in kernel/irq/:
1150 config GENERIC_HARDIRQS
1154 config GENERIC_IRQ_PROBE
1158 config GENERIC_PENDING_IRQ
1160 depends on GENERIC_HARDIRQS && SMP
1165 depends on SMP && !X86_VOYAGER
1170 depends on SMP && !(X86_VISWS || X86_VOYAGER || X86_XEN)
1173 config X86_BIOS_REBOOT
1175 depends on !(X86_VISWS || X86_VOYAGER)
1178 config X86_TRAMPOLINE
1180 depends on X86_SMP || (X86_VOYAGER && SMP)