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.
22 config LOCKDEP_SUPPORT
26 config STACKTRACE_SUPPORT
30 config SEMAPHORE_SLEEPERS
45 config GENERIC_ISA_DMA
53 config GENERIC_HWEIGHT
57 config ARCH_MAY_HAVE_PC_FDC
67 menu "Processor type and features"
70 bool "Symmetric multi-processing support"
72 This enables support for systems with more than one CPU. If you have
73 a system with only one CPU, like most personal computers, say N. If
74 you have a system with more than one CPU, say Y.
76 If you say N here, the kernel will run on single and multiprocessor
77 machines, but will use only one CPU of a multiprocessor machine. If
78 you say Y here, the kernel will run on many, but not all,
79 singleprocessor machines. On a singleprocessor machine, the kernel
80 will run faster if you say N here.
82 Note that if you say Y here and choose architecture "586" or
83 "Pentium" under "Processor family", the kernel will not work on 486
84 architectures. Similarly, multiprocessor kernels for the "PPro"
85 architecture may not work on all Pentium based boards.
87 People using multiprocessor machines who say Y here should also say
88 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
89 Management" code will be disabled if you say Y here.
91 See also the <file:Documentation/smp.txt>,
92 <file:Documentation/i386/IO-APIC.txt>,
93 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
94 <http://www.tldp.org/docs.html#howto>.
96 If you don't know what to do here, say N.
99 prompt "Subarchitecture Type"
105 Choose this option if your computer is a standard PC or compatible.
108 bool "Xen-compatible"
109 select X86_UP_APIC if !SMP && XEN_PRIVILEGED_GUEST
110 select X86_UP_IOAPIC if !SMP && XEN_PRIVILEGED_GUEST
113 Choose this option if you plan to run this kernel on top of the
119 Select this for an AMD Elan processor.
121 Do not use this option for K6/Athlon/Opteron processors!
123 If unsure, choose "PC-compatible" instead.
128 Voyager is an MCA-based 32-way capable SMP architecture proprietary
129 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
133 If you do not specifically know you have a Voyager based machine,
134 say N here, otherwise the kernel you build will not be bootable.
137 bool "NUMAQ (IBM/Sequent)"
141 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
142 multiquad box. This changes the way that processors are bootstrapped,
143 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
144 You will need a new lynxer.elf file to flash your firmware with - send
145 email to <Martin.Bligh@us.ibm.com>.
148 bool "Summit/EXA (IBM x440)"
151 This option is needed for IBM systems that use the Summit/EXA chipset.
152 In particular, it is needed for the x440.
154 If you don't have one of these computers, you should say N here.
155 If you want to build a NUMA kernel, you must select ACPI.
158 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
161 This option is needed for the systems that have more than 8 CPUs
162 and if the system is not of any sub-arch type above.
164 If you don't have such a system, you should say N here.
167 bool "SGI 320/540 (Visual Workstation)"
169 The SGI Visual Workstation series is an IA32-based workstation
170 based on SGI systems chips with some legacy PC hardware attached.
172 Say Y here to create a kernel to run on the SGI 320 or 540.
174 A kernel compiled for the Visual Workstation will not run on PCs
175 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
177 config X86_GENERICARCH
178 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
181 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
182 It is intended for a generic binary kernel.
183 If you want a NUMA kernel, select ACPI. We need SRAT for NUMA.
186 bool "Support for Unisys ES7000 IA32 series"
189 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
190 supposed to run on an IA32-based Unisys ES7000 system.
191 Only choose this option if you have such a system, otherwise you
199 depends on ACPI && NUMA && (X86_SUMMIT || X86_GENERICARCH)
202 config HAVE_ARCH_PARSE_SRAT
207 config X86_SUMMIT_NUMA
210 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
212 config X86_CYCLONE_TIMER
215 depends on X86_SUMMIT || X86_GENERICARCH
217 config ES7000_CLUSTERED_APIC
220 depends on SMP && X86_ES7000 && MPENTIUMIII
222 source "arch/i386/Kconfig.cpu"
225 bool "HPET Timer Support"
228 This enables the use of the HPET for the kernel's internal timer.
229 HPET is the next generation timer replacing legacy 8254s.
230 You can safely choose Y here. However, HPET will only be
231 activated if the platform and the BIOS support this feature.
232 Otherwise the 8254 will be used for timing services.
234 Choose N to continue using the legacy 8254 timer.
236 config HPET_EMULATE_RTC
238 depends on HPET_TIMER && RTC=y
242 int "Maximum number of CPUs (2-255)"
245 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
248 This allows you to specify the maximum number of CPUs which this
249 kernel will support. The maximum supported value is 255 and the
250 minimum value which makes sense is 2.
252 This is purely to save memory - each supported CPU adds
253 approximately eight kilobytes to the kernel image.
256 bool "SMT (Hyperthreading) scheduler support"
259 SMT scheduler support improves the CPU scheduler's decision making
260 when dealing with Intel Pentium 4 chips with HyperThreading at a
261 cost of slightly increased overhead in some places. If unsure say
265 bool "Multi-core scheduler support"
269 Multi-core scheduler support improves the CPU scheduler's decision
270 making when dealing with multi-core CPU chips at a cost of slightly
271 increased overhead in some places. If unsure say N here.
273 source "kernel/Kconfig.preempt"
276 bool "Local APIC support on uniprocessors"
277 depends on !SMP && !(X86_VISWS || X86_VOYAGER || XEN_UNPRIVILEGED_GUEST)
279 A local APIC (Advanced Programmable Interrupt Controller) is an
280 integrated interrupt controller in the CPU. If you have a single-CPU
281 system which has a processor with a local APIC, you can say Y here to
282 enable and use it. If you say Y here even though your machine doesn't
283 have a local APIC, then the kernel will still run with no slowdown at
284 all. The local APIC supports CPU-generated self-interrupts (timer,
285 performance counters), and the NMI watchdog which detects hard
289 bool "IO-APIC support on uniprocessors"
290 depends on X86_UP_APIC
292 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
293 SMP-capable replacement for PC-style interrupt controllers. Most
294 SMP systems and many recent uniprocessor systems have one.
296 If you have a single-CPU system with an IO-APIC, you can say Y here
297 to use it. If you say Y here even though your machine doesn't have
298 an IO-APIC, then the kernel will still run with no slowdown at all.
300 config X86_LOCAL_APIC
302 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !(X86_VOYAGER || XEN_UNPRIVILEGED_GUEST))
306 bool "Use heuristics to enable/disable local APIC"
307 depends on X86_LOCAL_APIC
309 This option uses some proven heuristics to automatically enable or disable the local
310 APIC. All decisions can be overriden by command line options.
311 In a nutshell very old systems run better with APIC off and newer or multiprocessor
312 systems prefer APIC on
313 This is a useful default for distribution kernels.
317 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER || XEN_UNPRIVILEGED_GUEST))
320 config X86_VISWS_APIC
326 bool "Machine Check Exception"
327 depends on !(X86_VOYAGER || X86_XEN)
329 Machine Check Exception support allows the processor to notify the
330 kernel if it detects a problem (e.g. overheating, component failure).
331 The action the kernel takes depends on the severity of the problem,
332 ranging from a warning message on the console, to halting the machine.
333 Your processor must be a Pentium or newer to support this - check the
334 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
335 have a design flaw which leads to false MCE events - hence MCE is
336 disabled on all P5 processors, unless explicitly enabled with "mce"
337 as a boot argument. Similarly, if MCE is built in and creates a
338 problem on some new non-standard machine, you can boot with "nomce"
339 to disable it. MCE support simply ignores non-MCE processors like
340 the 386 and 486, so nearly everyone can say Y here.
342 config X86_MCE_NONFATAL
343 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
346 Enabling this feature starts a timer that triggers every 5 seconds which
347 will look at the machine check registers to see if anything happened.
348 Non-fatal problems automatically get corrected (but still logged).
349 Disable this if you don't want to see these messages.
350 Seeing the messages this option prints out may be indicative of dying hardware,
351 or out-of-spec (ie, overclocked) hardware.
352 This option only does something on certain CPUs.
353 (AMD Athlon/Duron and Intel Pentium 4)
355 config X86_MCE_P4THERMAL
356 bool "check for P4 thermal throttling interrupt."
357 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
359 Enabling this feature will cause a message to be printed when the P4
360 enters thermal throttling.
364 bool "Enable VM86 support" if EMBEDDED
366 This option is required by programs like DOSEMU to run 16-bit legacy
367 code on X86 processors. It also may be needed by software like
368 XFree86 to initialize some video cards via BIOS. Disabling this
369 option saves about 6k.
372 tristate "Toshiba Laptop support"
374 This adds a driver to safely access the System Management Mode of
375 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
376 not work on models with a Phoenix BIOS. The System Management Mode
377 is used to set the BIOS and power saving options on Toshiba portables.
379 For information on utilities to make use of this driver see the
380 Toshiba Linux utilities web site at:
381 <http://www.buzzard.org.uk/toshiba/>.
383 Say Y if you intend to run this kernel on a Toshiba portable.
387 tristate "Dell laptop support"
389 This adds a driver to safely access the System Management Mode
390 of the CPU on the Dell Inspiron 8000. The System Management Mode
391 is used to read cpu temperature and cooling fan status and to
392 control the fans on the I8K portables.
394 This driver has been tested only on the Inspiron 8000 but it may
395 also work with other Dell laptops. You can force loading on other
396 models by passing the parameter `force=1' to the module. Use at
399 For information on utilities to make use of this driver see the
400 I8K Linux utilities web site at:
401 <http://people.debian.org/~dz/i8k/>
403 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
406 config X86_REBOOTFIXUPS
407 bool "Enable X86 board specific fixups for reboot"
411 This enables chipset and/or board specific fixups to be done
412 in order to get reboot to work correctly. This is only needed on
413 some combinations of hardware and BIOS. The symptom, for which
414 this config is intended, is when reboot ends with a stalled/hung
417 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
420 Say Y if you want to enable the fixup. Currently, it's safe to
421 enable this option even if you don't need it.
425 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
426 depends on !XEN_UNPRIVILEGED_GUEST
428 If you say Y here and also to "/dev file system support" in the
429 'File systems' section, you will be able to update the microcode on
430 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
431 Pentium III, Pentium 4, Xeon etc. You will obviously need the
432 actual microcode binary data itself which is not shipped with the
435 For latest news and information on obtaining all the required
436 ingredients for this driver, check:
437 <http://www.urbanmyth.org/microcode/>.
439 To compile this driver as a module, choose M here: the
440 module will be called microcode.
443 tristate "/dev/cpu/*/msr - Model-specific register support"
446 This device gives privileged processes access to the x86
447 Model-Specific Registers (MSRs). It is a character device with
448 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
449 MSR accesses are directed to a specific CPU on multi-processor
453 tristate "/dev/cpu/*/cpuid - CPU information support"
455 This device gives processes access to the x86 CPUID instruction to
456 be executed on a specific processor. It is a character device
457 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
464 source "drivers/firmware/Kconfig"
467 prompt "High Memory Support"
472 depends on !X86_NUMAQ
474 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
475 However, the address space of 32-bit x86 processors is only 4
476 Gigabytes large. That means that, if you have a large amount of
477 physical memory, not all of it can be "permanently mapped" by the
478 kernel. The physical memory that's not permanently mapped is called
481 If you are compiling a kernel which will never run on a machine with
482 more than 1 Gigabyte total physical RAM, answer "off" here (default
483 choice and suitable for most users). This will result in a "3GB/1GB"
484 split: 3GB are mapped so that each process sees a 3GB virtual memory
485 space and the remaining part of the 4GB virtual memory space is used
486 by the kernel to permanently map as much physical memory as
489 If the machine has between 1 and 4 Gigabytes physical RAM, then
492 If more than 4 Gigabytes is used then answer "64GB" here. This
493 selection turns Intel PAE (Physical Address Extension) mode on.
494 PAE implements 3-level paging on IA32 processors. PAE is fully
495 supported by Linux, PAE mode is implemented on all recent Intel
496 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
497 then the kernel will not boot on CPUs that don't support PAE!
499 The actual amount of total physical memory will either be
500 auto detected or can be forced by using a kernel command line option
501 such as "mem=256M". (Try "man bootparam" or see the documentation of
502 your boot loader (lilo or loadlin) about how to pass options to the
503 kernel at boot time.)
505 If unsure, say "off".
509 depends on !X86_NUMAQ
511 Select this if you have a 32-bit processor and between 1 and 4
512 gigabytes of physical RAM.
516 depends on X86_CMPXCHG64
518 Select this if you have a 32-bit processor and more than 4
519 gigabytes of physical RAM.
524 depends on EXPERIMENTAL && !X86_PAE
525 prompt "Memory split" if EMBEDDED
528 Select the desired split between kernel and user memory.
530 If the address range available to the kernel is less than the
531 physical memory installed, the remaining memory will be available
532 as "high memory". Accessing high memory is a little more costly
533 than low memory, as it needs to be mapped into the kernel first.
534 Note that increasing the kernel address space limits the range
535 available to user programs, making the address space there
536 tighter. Selecting anything other than the default 3G/1G split
537 will also likely make your kernel incompatible with binary-only
540 If you are not absolutely sure what you are doing, leave this
544 bool "3G/1G user/kernel split"
545 config VMSPLIT_3G_OPT
546 bool "3G/1G user/kernel split (for full 1G low memory)"
548 bool "2G/2G user/kernel split"
550 bool "1G/3G user/kernel split"
555 default 0xB0000000 if VMSPLIT_3G_OPT
556 default 0x78000000 if VMSPLIT_2G
557 default 0x40000000 if VMSPLIT_1G
562 depends on HIGHMEM64G || HIGHMEM4G
567 depends on HIGHMEM64G
569 select RESOURCES_64BIT
571 # Common NUMA Features
573 bool "Numa Memory Allocation and Scheduler Support"
574 depends on SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI)
576 default y if (X86_NUMAQ || X86_SUMMIT)
578 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
579 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
583 default "4" if X86_NUMAQ
585 depends on NEED_MULTIPLE_NODES
587 config HAVE_ARCH_BOOTMEM_NODE
592 config ARCH_HAVE_MEMORY_PRESENT
594 depends on DISCONTIGMEM
597 config NEED_NODE_MEMMAP_SIZE
599 depends on DISCONTIGMEM || SPARSEMEM
602 config HAVE_ARCH_ALLOC_REMAP
607 config ARCH_FLATMEM_ENABLE
609 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
611 config ARCH_DISCONTIGMEM_ENABLE
615 config ARCH_DISCONTIGMEM_DEFAULT
619 config ARCH_SPARSEMEM_ENABLE
621 depends on (NUMA || (X86_PC && EXPERIMENTAL))
622 select SPARSEMEM_STATIC
624 config ARCH_SELECT_MEMORY_MODEL
626 depends on ARCH_SPARSEMEM_ENABLE
630 config HAVE_ARCH_EARLY_PFN_TO_NID
636 bool "Allocate 3rd-level pagetables from highmem"
637 depends on (HIGHMEM4G || HIGHMEM64G) && !X86_XEN
639 The VM uses one page table entry for each page of physical memory.
640 For systems with a lot of RAM, this can be wasteful of precious
641 low memory. Setting this option will put user-space page table
642 entries in high memory.
644 config MATH_EMULATION
645 bool "Math emulation"
648 Linux can emulate a math coprocessor (used for floating point
649 operations) if you don't have one. 486DX and Pentium processors have
650 a math coprocessor built in, 486SX and 386 do not, unless you added
651 a 487DX or 387, respectively. (The messages during boot time can
652 give you some hints here ["man dmesg"].) Everyone needs either a
653 coprocessor or this emulation.
655 If you don't have a math coprocessor, you need to say Y here; if you
656 say Y here even though you have a coprocessor, the coprocessor will
657 be used nevertheless. (This behavior can be changed with the kernel
658 command line option "no387", which comes handy if your coprocessor
659 is broken. Try "man bootparam" or see the documentation of your boot
660 loader (lilo or loadlin) about how to pass options to the kernel at
661 boot time.) This means that it is a good idea to say Y here if you
662 intend to use this kernel on different machines.
664 More information about the internals of the Linux math coprocessor
665 emulation can be found in <file:arch/i386/math-emu/README>.
667 If you are not sure, say Y; apart from resulting in a 66 KB bigger
668 kernel, it won't hurt.
671 bool "MTRR (Memory Type Range Register) support"
672 depends on !XEN_UNPRIVILEGED_GUEST
675 On Intel P6 family processors (Pentium Pro, Pentium II and later)
676 the Memory Type Range Registers (MTRRs) may be used to control
677 processor access to memory ranges. This is most useful if you have
678 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
679 allows bus write transfers to be combined into a larger transfer
680 before bursting over the PCI/AGP bus. This can increase performance
681 of image write operations 2.5 times or more. Saying Y here creates a
682 /proc/mtrr file which may be used to manipulate your processor's
683 MTRRs. Typically the X server should use this.
685 This code has a reasonably generic interface so that similar
686 control registers on other processors can be easily supported
689 The Cyrix 6x86, 6x86MX and M II processors have Address Range
690 Registers (ARRs) which provide a similar functionality to MTRRs. For
691 these, the ARRs are used to emulate the MTRRs.
692 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
693 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
694 write-combining. All of these processors are supported by this code
695 and it makes sense to say Y here if you have one of them.
697 Saying Y here also fixes a problem with buggy SMP BIOSes which only
698 set the MTRRs for the boot CPU and not for the secondary CPUs. This
699 can lead to all sorts of problems, so it's good to say Y here.
701 You can safely say Y even if your machine doesn't have MTRRs, you'll
702 just add about 9 KB to your kernel.
704 See <file:Documentation/mtrr.txt> for more information.
707 bool "Boot from EFI support"
708 depends on ACPI && !X86_XEN
711 This enables the the kernel to boot on EFI platforms using
712 system configuration information passed to it from the firmware.
713 This also enables the kernel to use any EFI runtime services that are
714 available (such as the EFI variable services).
716 This option is only useful on systems that have EFI firmware
717 and will result in a kernel image that is ~8k larger. In addition,
718 you must use the latest ELILO loader available at
719 <http://elilo.sourceforge.net> in order to take advantage of
720 kernel initialization using EFI information (neither GRUB nor LILO know
721 anything about EFI). However, even with this option, the resultant
722 kernel should continue to boot on existing non-EFI platforms.
725 bool "Enable kernel irq balancing"
726 depends on SMP && X86_IO_APIC && !X86_XEN
729 The default yes will allow the kernel to do irq load balancing.
730 Saying no will keep the kernel from doing irq load balancing.
732 # turning this on wastes a bunch of space.
733 # Summit needs it only when NUMA is on
736 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
740 bool "Use register arguments"
743 Compile the kernel with -mregparm=3. This instructs gcc to use
744 a more efficient function call ABI which passes the first three
745 arguments of a function call via registers, which results in denser
748 If this option is disabled, then the default ABI of passing
749 arguments via the stack is used.
754 bool "Enable seccomp to safely compute untrusted bytecode"
758 This kernel feature is useful for number crunching applications
759 that may need to compute untrusted bytecode during their
760 execution. By using pipes or other transports made available to
761 the process as file descriptors supporting the read/write
762 syscalls, it's possible to isolate those applications in
763 their own address space using seccomp. Once seccomp is
764 enabled via /proc/<pid>/seccomp, it cannot be disabled
765 and the task is only allowed to execute a few safe syscalls
766 defined by each seccomp mode.
768 If unsure, say Y. Only embedded should say N here.
770 source kernel/Kconfig.hz
773 bool "kexec system call (EXPERIMENTAL)"
774 depends on EXPERIMENTAL && !X86_XEN
776 kexec is a system call that implements the ability to shutdown your
777 current kernel, and to start another kernel. It is like a reboot
778 but it is independent of the system firmware. And like a reboot
779 you can start any kernel with it, not just Linux.
781 The name comes from the similarity to the exec system call.
783 It is an ongoing process to be certain the hardware in a machine
784 is properly shutdown, so do not be surprised if this code does not
785 initially work for you. It may help to enable device hotplugging
786 support. As of this writing the exact hardware interface is
787 strongly in flux, so no good recommendation can be made.
790 bool "kernel crash dumps (EXPERIMENTAL)"
791 depends on EXPERIMENTAL
794 Generate crash dump after being started by kexec.
796 config PHYSICAL_START
797 hex "Physical address where the kernel is loaded"
799 default "0x1000000" if CRASH_DUMP
802 This gives the physical address where the kernel is loaded. Normally
803 for regular kernels this value is 0x100000 (1MB). But in the case
804 of kexec on panic the fail safe kernel needs to run at a different
805 address than the panic-ed kernel. This option is used to set the load
806 address for kernels used to capture crash dump on being kexec'ed
807 after panic. The default value for crash dump kernels is
808 0x1000000 (16MB). This can also be set based on the "X" value as
809 specified in the "crashkernel=YM@XM" command line boot parameter
810 passed to the panic-ed kernel. Typically this parameter is set as
811 crashkernel=64M@16M. Please take a look at
812 Documentation/kdump/kdump.txt for more details about crash dumps.
814 Don't change this unless you know what you are doing.
817 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
818 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
820 Say Y here to experiment with turning CPUs off and on, and to
821 enable suspend on SMP systems. CPUs can be controlled through
822 /sys/devices/system/cpu.
825 bool "Compat VDSO support"
829 Map the VDSO to the predictable old-style address too.
831 Say N here if you are running a sufficiently recent glibc
832 version (2.3.3 or later), to remove the high-mapped
833 VDSO mapping and to exclusively use the randomized VDSO.
839 config ARCH_ENABLE_MEMORY_HOTPLUG
843 menu "Power management options (ACPI, APM)"
844 depends on !(X86_VOYAGER || XEN_UNPRIVILEGED_GUEST)
847 source kernel/power/Kconfig
850 source "drivers/acpi/Kconfig"
852 menu "APM (Advanced Power Management) BIOS Support"
853 depends on PM && !(X86_VISWS || X86_XEN)
856 tristate "APM (Advanced Power Management) BIOS support"
857 depends on PM && PM_LEGACY
859 APM is a BIOS specification for saving power using several different
860 techniques. This is mostly useful for battery powered laptops with
861 APM compliant BIOSes. If you say Y here, the system time will be
862 reset after a RESUME operation, the /proc/apm device will provide
863 battery status information, and user-space programs will receive
864 notification of APM "events" (e.g. battery status change).
866 If you select "Y" here, you can disable actual use of the APM
867 BIOS by passing the "apm=off" option to the kernel at boot time.
869 Note that the APM support is almost completely disabled for
870 machines with more than one CPU.
872 In order to use APM, you will need supporting software. For location
873 and more information, read <file:Documentation/pm.txt> and the
874 Battery Powered Linux mini-HOWTO, available from
875 <http://www.tldp.org/docs.html#howto>.
877 This driver does not spin down disk drives (see the hdparm(8)
878 manpage ("man 8 hdparm") for that), and it doesn't turn off
879 VESA-compliant "green" monitors.
881 This driver does not support the TI 4000M TravelMate and the ACER
882 486/DX4/75 because they don't have compliant BIOSes. Many "green"
883 desktop machines also don't have compliant BIOSes, and this driver
884 may cause those machines to panic during the boot phase.
886 Generally, if you don't have a battery in your machine, there isn't
887 much point in using this driver and you should say N. If you get
888 random kernel OOPSes or reboots that don't seem to be related to
889 anything, try disabling/enabling this option (or disabling/enabling
892 Some other things you should try when experiencing seemingly random,
895 1) make sure that you have enough swap space and that it is
897 2) pass the "no-hlt" option to the kernel
898 3) switch on floating point emulation in the kernel and pass
899 the "no387" option to the kernel
900 4) pass the "floppy=nodma" option to the kernel
901 5) pass the "mem=4M" option to the kernel (thereby disabling
902 all but the first 4 MB of RAM)
903 6) make sure that the CPU is not over clocked.
904 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
905 8) disable the cache from your BIOS settings
906 9) install a fan for the video card or exchange video RAM
907 10) install a better fan for the CPU
908 11) exchange RAM chips
909 12) exchange the motherboard.
911 To compile this driver as a module, choose M here: the
912 module will be called apm.
914 config APM_IGNORE_USER_SUSPEND
915 bool "Ignore USER SUSPEND"
918 This option will ignore USER SUSPEND requests. On machines with a
919 compliant APM BIOS, you want to say N. However, on the NEC Versa M
920 series notebooks, it is necessary to say Y because of a BIOS bug.
923 bool "Enable PM at boot time"
926 Enable APM features at boot time. From page 36 of the APM BIOS
927 specification: "When disabled, the APM BIOS does not automatically
928 power manage devices, enter the Standby State, enter the Suspend
929 State, or take power saving steps in response to CPU Idle calls."
930 This driver will make CPU Idle calls when Linux is idle (unless this
931 feature is turned off -- see "Do CPU IDLE calls", below). This
932 should always save battery power, but more complicated APM features
933 will be dependent on your BIOS implementation. You may need to turn
934 this option off if your computer hangs at boot time when using APM
935 support, or if it beeps continuously instead of suspending. Turn
936 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
937 T400CDT. This is off by default since most machines do fine without
941 bool "Make CPU Idle calls when idle"
944 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
945 On some machines, this can activate improved power savings, such as
946 a slowed CPU clock rate, when the machine is idle. These idle calls
947 are made after the idle loop has run for some length of time (e.g.,
948 333 mS). On some machines, this will cause a hang at boot time or
949 whenever the CPU becomes idle. (On machines with more than one CPU,
950 this option does nothing.)
952 config APM_DISPLAY_BLANK
953 bool "Enable console blanking using APM"
956 Enable console blanking using the APM. Some laptops can use this to
957 turn off the LCD backlight when the screen blanker of the Linux
958 virtual console blanks the screen. Note that this is only used by
959 the virtual console screen blanker, and won't turn off the backlight
960 when using the X Window system. This also doesn't have anything to
961 do with your VESA-compliant power-saving monitor. Further, this
962 option doesn't work for all laptops -- it might not turn off your
963 backlight at all, or it might print a lot of errors to the console,
964 especially if you are using gpm.
966 config APM_RTC_IS_GMT
967 bool "RTC stores time in GMT"
970 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
971 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
974 It is in fact recommended to store GMT in your RTC, because then you
975 don't have to worry about daylight savings time changes. The only
976 reason not to use GMT in your RTC is if you also run a broken OS
977 that doesn't understand GMT.
979 config APM_ALLOW_INTS
980 bool "Allow interrupts during APM BIOS calls"
983 Normally we disable external interrupts while we are making calls to
984 the APM BIOS as a measure to lessen the effects of a badly behaving
985 BIOS implementation. The BIOS should reenable interrupts if it
986 needs to. Unfortunately, some BIOSes do not -- especially those in
987 many of the newer IBM Thinkpads. If you experience hangs when you
988 suspend, try setting this to Y. Otherwise, say N.
990 config APM_REAL_MODE_POWER_OFF
991 bool "Use real mode APM BIOS call to power off"
994 Use real mode APM BIOS calls to switch off the computer. This is
995 a work-around for a number of buggy BIOSes. Switch this option on if
996 your computer crashes instead of powering off properly.
1000 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1004 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1007 bool "PCI support" if !X86_VISWS
1008 depends on !X86_VOYAGER
1009 default y if X86_VISWS
1011 Find out whether you have a PCI motherboard. PCI is the name of a
1012 bus system, i.e. the way the CPU talks to the other stuff inside
1013 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1014 VESA. If you have PCI, say Y, otherwise N.
1016 The PCI-HOWTO, available from
1017 <http://www.tldp.org/docs.html#howto>, contains valuable
1018 information about which PCI hardware does work under Linux and which
1022 prompt "PCI access mode"
1023 depends on PCI && !X86_VISWS
1026 On PCI systems, the BIOS can be used to detect the PCI devices and
1027 determine their configuration. However, some old PCI motherboards
1028 have BIOS bugs and may crash if this is done. Also, some embedded
1029 PCI-based systems don't have any BIOS at all. Linux can also try to
1030 detect the PCI hardware directly without using the BIOS.
1032 With this option, you can specify how Linux should detect the
1033 PCI devices. If you choose "BIOS", the BIOS will be used,
1034 if you choose "Direct", the BIOS won't be used, and if you
1035 choose "MMConfig", then PCI Express MMCONFIG will be used.
1036 If you choose "Any", the kernel will try MMCONFIG, then the
1037 direct access method and falls back to the BIOS if that doesn't
1038 work. If unsure, go with the default, which is "Any".
1044 config PCI_GOMMCONFIG
1051 bool "Xen PCI Frontend"
1054 The PCI device frontend driver allows the kernel to import arbitrary
1055 PCI devices from a PCI backend to support PCI driver domains.
1064 depends on !(X86_VISWS || X86_XEN) && PCI && (PCI_GOBIOS || PCI_GOANY)
1069 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1074 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1077 config XEN_PCIDEV_FRONTEND
1079 depends on PCI && X86_XEN && (PCI_GOXEN_FE || PCI_GOANY)
1082 config XEN_PCIDEV_FE_DEBUG
1083 bool "Xen PCI Frontend Debugging"
1084 depends on XEN_PCIDEV_FRONTEND
1087 Enables some debug statements within the PCI Frontend.
1089 source "drivers/pci/pcie/Kconfig"
1091 source "drivers/pci/Kconfig"
1099 depends on !(X86_VOYAGER || X86_VISWS || X86_XEN)
1101 Find out whether you have ISA slots on your motherboard. ISA is the
1102 name of a bus system, i.e. the way the CPU talks to the other stuff
1103 inside your box. Other bus systems are PCI, EISA, MicroChannel
1104 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1105 newer boards don't support it. If you have ISA, say Y, otherwise N.
1111 The Extended Industry Standard Architecture (EISA) bus was
1112 developed as an open alternative to the IBM MicroChannel bus.
1114 The EISA bus provided some of the features of the IBM MicroChannel
1115 bus while maintaining backward compatibility with cards made for
1116 the older ISA bus. The EISA bus saw limited use between 1988 and
1117 1995 when it was made obsolete by the PCI bus.
1119 Say Y here if you are building a kernel for an EISA-based machine.
1123 source "drivers/eisa/Kconfig"
1126 bool "MCA support" if !(X86_VISWS || X86_VOYAGER || X86_XEN)
1127 default y if X86_VOYAGER
1129 MicroChannel Architecture is found in some IBM PS/2 machines and
1130 laptops. It is a bus system similar to PCI or ISA. See
1131 <file:Documentation/mca.txt> (and especially the web page given
1132 there) before attempting to build an MCA bus kernel.
1134 source "drivers/mca/Kconfig"
1137 tristate "NatSemi SCx200 support"
1138 depends on !X86_VOYAGER
1140 This provides basic support for National Semiconductor's
1141 (now AMD's) Geode processors. The driver probes for the
1142 PCI-IDs of several on-chip devices, so its a good dependency
1143 for other scx200_* drivers.
1145 If compiled as a module, the driver is named scx200.
1147 config SCx200HR_TIMER
1148 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1149 depends on SCx200 && GENERIC_TIME
1152 This driver provides a clocksource built upon the on-chip
1153 27MHz high-resolution timer. Its also a workaround for
1154 NSC Geode SC-1100's buggy TSC, which loses time when the
1155 processor goes idle (as is done by the scheduler). The
1156 other workaround is idle=poll boot option.
1160 depends on AGP_AMD64
1162 source "drivers/pcmcia/Kconfig"
1164 source "drivers/pci/hotplug/Kconfig"
1168 menu "Executable file formats"
1170 source "fs/Kconfig.binfmt"
1174 source "net/Kconfig"
1176 source "drivers/Kconfig"
1180 menu "Instrumentation Support"
1181 depends on EXPERIMENTAL
1183 source "arch/i386/oprofile/Kconfig"
1186 bool "Kprobes (EXPERIMENTAL)"
1187 depends on EXPERIMENTAL && MODULES
1189 Kprobes allows you to trap at almost any kernel address and
1190 execute a callback function. register_kprobe() establishes
1191 a probepoint and specifies the callback. Kprobes is useful
1192 for kernel debugging, non-intrusive instrumentation and testing.
1193 If in doubt, say "N".
1196 source "arch/i386/Kconfig.debug"
1198 source "kernel/vserver/Kconfig"
1200 source "security/Kconfig"
1202 source "crypto/Kconfig"
1204 source "drivers/xen/Kconfig"
1206 source "lib/Kconfig"
1209 # Use the generic interrupt handling code in kernel/irq/:
1211 config GENERIC_HARDIRQS
1215 config GENERIC_IRQ_PROBE
1219 config GENERIC_PENDING_IRQ
1221 depends on GENERIC_HARDIRQS && SMP
1226 depends on SMP && !X86_VOYAGER
1231 depends on SMP && !(X86_VISWS || X86_VOYAGER || X86_XEN)
1234 config X86_BIOS_REBOOT
1236 depends on !(X86_VISWS || X86_VOYAGER)
1239 config X86_TRAMPOLINE
1241 depends on X86_SMP || (X86_VOYAGER && SMP)