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))
307 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER || XEN_UNPRIVILEGED_GUEST))
310 config X86_VISWS_APIC
316 bool "Machine Check Exception"
317 depends on !(X86_VOYAGER || X86_XEN)
319 Machine Check Exception support allows the processor to notify the
320 kernel if it detects a problem (e.g. overheating, component failure).
321 The action the kernel takes depends on the severity of the problem,
322 ranging from a warning message on the console, to halting the machine.
323 Your processor must be a Pentium or newer to support this - check the
324 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
325 have a design flaw which leads to false MCE events - hence MCE is
326 disabled on all P5 processors, unless explicitly enabled with "mce"
327 as a boot argument. Similarly, if MCE is built in and creates a
328 problem on some new non-standard machine, you can boot with "nomce"
329 to disable it. MCE support simply ignores non-MCE processors like
330 the 386 and 486, so nearly everyone can say Y here.
332 config X86_MCE_NONFATAL
333 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
336 Enabling this feature starts a timer that triggers every 5 seconds which
337 will look at the machine check registers to see if anything happened.
338 Non-fatal problems automatically get corrected (but still logged).
339 Disable this if you don't want to see these messages.
340 Seeing the messages this option prints out may be indicative of dying hardware,
341 or out-of-spec (ie, overclocked) hardware.
342 This option only does something on certain CPUs.
343 (AMD Athlon/Duron and Intel Pentium 4)
345 config X86_MCE_P4THERMAL
346 bool "check for P4 thermal throttling interrupt."
347 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
349 Enabling this feature will cause a message to be printed when the P4
350 enters thermal throttling.
354 bool "Enable VM86 support" if EMBEDDED
356 This option is required by programs like DOSEMU to run 16-bit legacy
357 code on X86 processors. It also may be needed by software like
358 XFree86 to initialize some video cards via BIOS. Disabling this
359 option saves about 6k.
362 tristate "Toshiba Laptop support"
364 This adds a driver to safely access the System Management Mode of
365 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
366 not work on models with a Phoenix BIOS. The System Management Mode
367 is used to set the BIOS and power saving options on Toshiba portables.
369 For information on utilities to make use of this driver see the
370 Toshiba Linux utilities web site at:
371 <http://www.buzzard.org.uk/toshiba/>.
373 Say Y if you intend to run this kernel on a Toshiba portable.
377 tristate "Dell laptop support"
379 This adds a driver to safely access the System Management Mode
380 of the CPU on the Dell Inspiron 8000. The System Management Mode
381 is used to read cpu temperature and cooling fan status and to
382 control the fans on the I8K portables.
384 This driver has been tested only on the Inspiron 8000 but it may
385 also work with other Dell laptops. You can force loading on other
386 models by passing the parameter `force=1' to the module. Use at
389 For information on utilities to make use of this driver see the
390 I8K Linux utilities web site at:
391 <http://people.debian.org/~dz/i8k/>
393 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
396 config X86_REBOOTFIXUPS
397 bool "Enable X86 board specific fixups for reboot"
401 This enables chipset and/or board specific fixups to be done
402 in order to get reboot to work correctly. This is only needed on
403 some combinations of hardware and BIOS. The symptom, for which
404 this config is intended, is when reboot ends with a stalled/hung
407 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
410 Say Y if you want to enable the fixup. Currently, it's safe to
411 enable this option even if you don't need it.
415 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
416 depends on !XEN_UNPRIVILEGED_GUEST
418 If you say Y here and also to "/dev file system support" in the
419 'File systems' section, you will be able to update the microcode on
420 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
421 Pentium III, Pentium 4, Xeon etc. You will obviously need the
422 actual microcode binary data itself which is not shipped with the
425 For latest news and information on obtaining all the required
426 ingredients for this driver, check:
427 <http://www.urbanmyth.org/microcode/>.
429 To compile this driver as a module, choose M here: the
430 module will be called microcode.
433 tristate "/dev/cpu/*/msr - Model-specific register support"
436 This device gives privileged processes access to the x86
437 Model-Specific Registers (MSRs). It is a character device with
438 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
439 MSR accesses are directed to a specific CPU on multi-processor
443 tristate "/dev/cpu/*/cpuid - CPU information support"
445 This device gives processes access to the x86 CPUID instruction to
446 be executed on a specific processor. It is a character device
447 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
454 source "drivers/firmware/Kconfig"
457 prompt "High Memory Support"
462 depends on !X86_NUMAQ
464 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
465 However, the address space of 32-bit x86 processors is only 4
466 Gigabytes large. That means that, if you have a large amount of
467 physical memory, not all of it can be "permanently mapped" by the
468 kernel. The physical memory that's not permanently mapped is called
471 If you are compiling a kernel which will never run on a machine with
472 more than 1 Gigabyte total physical RAM, answer "off" here (default
473 choice and suitable for most users). This will result in a "3GB/1GB"
474 split: 3GB are mapped so that each process sees a 3GB virtual memory
475 space and the remaining part of the 4GB virtual memory space is used
476 by the kernel to permanently map as much physical memory as
479 If the machine has between 1 and 4 Gigabytes physical RAM, then
482 If more than 4 Gigabytes is used then answer "64GB" here. This
483 selection turns Intel PAE (Physical Address Extension) mode on.
484 PAE implements 3-level paging on IA32 processors. PAE is fully
485 supported by Linux, PAE mode is implemented on all recent Intel
486 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
487 then the kernel will not boot on CPUs that don't support PAE!
489 The actual amount of total physical memory will either be
490 auto detected or can be forced by using a kernel command line option
491 such as "mem=256M". (Try "man bootparam" or see the documentation of
492 your boot loader (lilo or loadlin) about how to pass options to the
493 kernel at boot time.)
495 If unsure, say "off".
499 depends on !X86_NUMAQ
501 Select this if you have a 32-bit processor and between 1 and 4
502 gigabytes of physical RAM.
506 depends on X86_CMPXCHG64
508 Select this if you have a 32-bit processor and more than 4
509 gigabytes of physical RAM.
514 depends on EXPERIMENTAL && !X86_PAE
515 prompt "Memory split" if EMBEDDED
518 Select the desired split between kernel and user memory.
520 If the address range available to the kernel is less than the
521 physical memory installed, the remaining memory will be available
522 as "high memory". Accessing high memory is a little more costly
523 than low memory, as it needs to be mapped into the kernel first.
524 Note that increasing the kernel address space limits the range
525 available to user programs, making the address space there
526 tighter. Selecting anything other than the default 3G/1G split
527 will also likely make your kernel incompatible with binary-only
530 If you are not absolutely sure what you are doing, leave this
534 bool "3G/1G user/kernel split"
535 config VMSPLIT_3G_OPT
536 bool "3G/1G user/kernel split (for full 1G low memory)"
538 bool "2G/2G user/kernel split"
540 bool "1G/3G user/kernel split"
545 default 0xB0000000 if VMSPLIT_3G_OPT
546 default 0x78000000 if VMSPLIT_2G
547 default 0x40000000 if VMSPLIT_1G
552 depends on HIGHMEM64G || HIGHMEM4G
557 depends on HIGHMEM64G
559 select RESOURCES_64BIT
561 # Common NUMA Features
563 bool "Numa Memory Allocation and Scheduler Support"
564 depends on SMP && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI)
566 default y if (X86_NUMAQ || X86_SUMMIT)
568 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
569 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
573 default "4" if X86_NUMAQ
575 depends on NEED_MULTIPLE_NODES
577 config HAVE_ARCH_BOOTMEM_NODE
582 config ARCH_HAVE_MEMORY_PRESENT
584 depends on DISCONTIGMEM
587 config NEED_NODE_MEMMAP_SIZE
589 depends on DISCONTIGMEM || SPARSEMEM
592 config HAVE_ARCH_ALLOC_REMAP
597 config ARCH_FLATMEM_ENABLE
599 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
601 config ARCH_DISCONTIGMEM_ENABLE
605 config ARCH_DISCONTIGMEM_DEFAULT
609 config ARCH_SPARSEMEM_ENABLE
611 depends on (NUMA || (X86_PC && EXPERIMENTAL))
612 select SPARSEMEM_STATIC
614 config ARCH_SELECT_MEMORY_MODEL
616 depends on ARCH_SPARSEMEM_ENABLE
620 config HAVE_ARCH_EARLY_PFN_TO_NID
626 bool "Allocate 3rd-level pagetables from highmem"
627 depends on (HIGHMEM4G || HIGHMEM64G) && !X86_XEN
629 The VM uses one page table entry for each page of physical memory.
630 For systems with a lot of RAM, this can be wasteful of precious
631 low memory. Setting this option will put user-space page table
632 entries in high memory.
634 config MATH_EMULATION
635 bool "Math emulation"
638 Linux can emulate a math coprocessor (used for floating point
639 operations) if you don't have one. 486DX and Pentium processors have
640 a math coprocessor built in, 486SX and 386 do not, unless you added
641 a 487DX or 387, respectively. (The messages during boot time can
642 give you some hints here ["man dmesg"].) Everyone needs either a
643 coprocessor or this emulation.
645 If you don't have a math coprocessor, you need to say Y here; if you
646 say Y here even though you have a coprocessor, the coprocessor will
647 be used nevertheless. (This behavior can be changed with the kernel
648 command line option "no387", which comes handy if your coprocessor
649 is broken. Try "man bootparam" or see the documentation of your boot
650 loader (lilo or loadlin) about how to pass options to the kernel at
651 boot time.) This means that it is a good idea to say Y here if you
652 intend to use this kernel on different machines.
654 More information about the internals of the Linux math coprocessor
655 emulation can be found in <file:arch/i386/math-emu/README>.
657 If you are not sure, say Y; apart from resulting in a 66 KB bigger
658 kernel, it won't hurt.
661 bool "MTRR (Memory Type Range Register) support"
662 depends on !XEN_UNPRIVILEGED_GUEST
665 On Intel P6 family processors (Pentium Pro, Pentium II and later)
666 the Memory Type Range Registers (MTRRs) may be used to control
667 processor access to memory ranges. This is most useful if you have
668 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
669 allows bus write transfers to be combined into a larger transfer
670 before bursting over the PCI/AGP bus. This can increase performance
671 of image write operations 2.5 times or more. Saying Y here creates a
672 /proc/mtrr file which may be used to manipulate your processor's
673 MTRRs. Typically the X server should use this.
675 This code has a reasonably generic interface so that similar
676 control registers on other processors can be easily supported
679 The Cyrix 6x86, 6x86MX and M II processors have Address Range
680 Registers (ARRs) which provide a similar functionality to MTRRs. For
681 these, the ARRs are used to emulate the MTRRs.
682 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
683 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
684 write-combining. All of these processors are supported by this code
685 and it makes sense to say Y here if you have one of them.
687 Saying Y here also fixes a problem with buggy SMP BIOSes which only
688 set the MTRRs for the boot CPU and not for the secondary CPUs. This
689 can lead to all sorts of problems, so it's good to say Y here.
691 You can safely say Y even if your machine doesn't have MTRRs, you'll
692 just add about 9 KB to your kernel.
694 See <file:Documentation/mtrr.txt> for more information.
697 bool "Boot from EFI support"
698 depends on ACPI && !X86_XEN
701 This enables the the kernel to boot on EFI platforms using
702 system configuration information passed to it from the firmware.
703 This also enables the kernel to use any EFI runtime services that are
704 available (such as the EFI variable services).
706 This option is only useful on systems that have EFI firmware
707 and will result in a kernel image that is ~8k larger. In addition,
708 you must use the latest ELILO loader available at
709 <http://elilo.sourceforge.net> in order to take advantage of
710 kernel initialization using EFI information (neither GRUB nor LILO know
711 anything about EFI). However, even with this option, the resultant
712 kernel should continue to boot on existing non-EFI platforms.
715 bool "Enable kernel irq balancing"
716 depends on SMP && X86_IO_APIC && !X86_XEN
719 The default yes will allow the kernel to do irq load balancing.
720 Saying no will keep the kernel from doing irq load balancing.
722 # turning this on wastes a bunch of space.
723 # Summit needs it only when NUMA is on
726 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
730 bool "Use register arguments"
733 Compile the kernel with -mregparm=3. This instructs gcc to use
734 a more efficient function call ABI which passes the first three
735 arguments of a function call via registers, which results in denser
738 If this option is disabled, then the default ABI of passing
739 arguments via the stack is used.
744 bool "Enable seccomp to safely compute untrusted bytecode"
748 This kernel feature is useful for number crunching applications
749 that may need to compute untrusted bytecode during their
750 execution. By using pipes or other transports made available to
751 the process as file descriptors supporting the read/write
752 syscalls, it's possible to isolate those applications in
753 their own address space using seccomp. Once seccomp is
754 enabled via /proc/<pid>/seccomp, it cannot be disabled
755 and the task is only allowed to execute a few safe syscalls
756 defined by each seccomp mode.
758 If unsure, say Y. Only embedded should say N here.
760 source kernel/Kconfig.hz
763 bool "kexec system call (EXPERIMENTAL)"
764 depends on EXPERIMENTAL && !X86_XEN
766 kexec is a system call that implements the ability to shutdown your
767 current kernel, and to start another kernel. It is like a reboot
768 but it is independent of the system firmware. And like a reboot
769 you can start any kernel with it, not just Linux.
771 The name comes from the similarity to the exec system call.
773 It is an ongoing process to be certain the hardware in a machine
774 is properly shutdown, so do not be surprised if this code does not
775 initially work for you. It may help to enable device hotplugging
776 support. As of this writing the exact hardware interface is
777 strongly in flux, so no good recommendation can be made.
780 bool "kernel crash dumps (EXPERIMENTAL)"
781 depends on EXPERIMENTAL
784 Generate crash dump after being started by kexec.
786 config PHYSICAL_START
787 hex "Physical address where the kernel is loaded"
789 default "0x1000000" if CRASH_DUMP
792 This gives the physical address where the kernel is loaded. Normally
793 for regular kernels this value is 0x100000 (1MB). But in the case
794 of kexec on panic the fail safe kernel needs to run at a different
795 address than the panic-ed kernel. This option is used to set the load
796 address for kernels used to capture crash dump on being kexec'ed
797 after panic. The default value for crash dump kernels is
798 0x1000000 (16MB). This can also be set based on the "X" value as
799 specified in the "crashkernel=YM@XM" command line boot parameter
800 passed to the panic-ed kernel. Typically this parameter is set as
801 crashkernel=64M@16M. Please take a look at
802 Documentation/kdump/kdump.txt for more details about crash dumps.
804 Don't change this unless you know what you are doing.
807 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
808 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
810 Say Y here to experiment with turning CPUs off and on, and to
811 enable suspend on SMP systems. CPUs can be controlled through
812 /sys/devices/system/cpu.
815 bool "Compat VDSO support"
819 Map the VDSO to the predictable old-style address too.
821 Say N here if you are running a sufficiently recent glibc
822 version (2.3.3 or later), to remove the high-mapped
823 VDSO mapping and to exclusively use the randomized VDSO.
829 config ARCH_ENABLE_MEMORY_HOTPLUG
833 menu "Power management options (ACPI, APM)"
834 depends on !(X86_VOYAGER || XEN_UNPRIVILEGED_GUEST)
837 source kernel/power/Kconfig
840 source "drivers/acpi/Kconfig"
842 menu "APM (Advanced Power Management) BIOS Support"
843 depends on PM && !(X86_VISWS || X86_XEN)
846 tristate "APM (Advanced Power Management) BIOS support"
847 depends on PM && PM_LEGACY
849 APM is a BIOS specification for saving power using several different
850 techniques. This is mostly useful for battery powered laptops with
851 APM compliant BIOSes. If you say Y here, the system time will be
852 reset after a RESUME operation, the /proc/apm device will provide
853 battery status information, and user-space programs will receive
854 notification of APM "events" (e.g. battery status change).
856 If you select "Y" here, you can disable actual use of the APM
857 BIOS by passing the "apm=off" option to the kernel at boot time.
859 Note that the APM support is almost completely disabled for
860 machines with more than one CPU.
862 In order to use APM, you will need supporting software. For location
863 and more information, read <file:Documentation/pm.txt> and the
864 Battery Powered Linux mini-HOWTO, available from
865 <http://www.tldp.org/docs.html#howto>.
867 This driver does not spin down disk drives (see the hdparm(8)
868 manpage ("man 8 hdparm") for that), and it doesn't turn off
869 VESA-compliant "green" monitors.
871 This driver does not support the TI 4000M TravelMate and the ACER
872 486/DX4/75 because they don't have compliant BIOSes. Many "green"
873 desktop machines also don't have compliant BIOSes, and this driver
874 may cause those machines to panic during the boot phase.
876 Generally, if you don't have a battery in your machine, there isn't
877 much point in using this driver and you should say N. If you get
878 random kernel OOPSes or reboots that don't seem to be related to
879 anything, try disabling/enabling this option (or disabling/enabling
882 Some other things you should try when experiencing seemingly random,
885 1) make sure that you have enough swap space and that it is
887 2) pass the "no-hlt" option to the kernel
888 3) switch on floating point emulation in the kernel and pass
889 the "no387" option to the kernel
890 4) pass the "floppy=nodma" option to the kernel
891 5) pass the "mem=4M" option to the kernel (thereby disabling
892 all but the first 4 MB of RAM)
893 6) make sure that the CPU is not over clocked.
894 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
895 8) disable the cache from your BIOS settings
896 9) install a fan for the video card or exchange video RAM
897 10) install a better fan for the CPU
898 11) exchange RAM chips
899 12) exchange the motherboard.
901 To compile this driver as a module, choose M here: the
902 module will be called apm.
904 config APM_IGNORE_USER_SUSPEND
905 bool "Ignore USER SUSPEND"
908 This option will ignore USER SUSPEND requests. On machines with a
909 compliant APM BIOS, you want to say N. However, on the NEC Versa M
910 series notebooks, it is necessary to say Y because of a BIOS bug.
913 bool "Enable PM at boot time"
916 Enable APM features at boot time. From page 36 of the APM BIOS
917 specification: "When disabled, the APM BIOS does not automatically
918 power manage devices, enter the Standby State, enter the Suspend
919 State, or take power saving steps in response to CPU Idle calls."
920 This driver will make CPU Idle calls when Linux is idle (unless this
921 feature is turned off -- see "Do CPU IDLE calls", below). This
922 should always save battery power, but more complicated APM features
923 will be dependent on your BIOS implementation. You may need to turn
924 this option off if your computer hangs at boot time when using APM
925 support, or if it beeps continuously instead of suspending. Turn
926 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
927 T400CDT. This is off by default since most machines do fine without
931 bool "Make CPU Idle calls when idle"
934 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
935 On some machines, this can activate improved power savings, such as
936 a slowed CPU clock rate, when the machine is idle. These idle calls
937 are made after the idle loop has run for some length of time (e.g.,
938 333 mS). On some machines, this will cause a hang at boot time or
939 whenever the CPU becomes idle. (On machines with more than one CPU,
940 this option does nothing.)
942 config APM_DISPLAY_BLANK
943 bool "Enable console blanking using APM"
946 Enable console blanking using the APM. Some laptops can use this to
947 turn off the LCD backlight when the screen blanker of the Linux
948 virtual console blanks the screen. Note that this is only used by
949 the virtual console screen blanker, and won't turn off the backlight
950 when using the X Window system. This also doesn't have anything to
951 do with your VESA-compliant power-saving monitor. Further, this
952 option doesn't work for all laptops -- it might not turn off your
953 backlight at all, or it might print a lot of errors to the console,
954 especially if you are using gpm.
956 config APM_RTC_IS_GMT
957 bool "RTC stores time in GMT"
960 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
961 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
964 It is in fact recommended to store GMT in your RTC, because then you
965 don't have to worry about daylight savings time changes. The only
966 reason not to use GMT in your RTC is if you also run a broken OS
967 that doesn't understand GMT.
969 config APM_ALLOW_INTS
970 bool "Allow interrupts during APM BIOS calls"
973 Normally we disable external interrupts while we are making calls to
974 the APM BIOS as a measure to lessen the effects of a badly behaving
975 BIOS implementation. The BIOS should reenable interrupts if it
976 needs to. Unfortunately, some BIOSes do not -- especially those in
977 many of the newer IBM Thinkpads. If you experience hangs when you
978 suspend, try setting this to Y. Otherwise, say N.
980 config APM_REAL_MODE_POWER_OFF
981 bool "Use real mode APM BIOS call to power off"
984 Use real mode APM BIOS calls to switch off the computer. This is
985 a work-around for a number of buggy BIOSes. Switch this option on if
986 your computer crashes instead of powering off properly.
990 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
994 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
997 bool "PCI support" if !X86_VISWS
998 depends on !X86_VOYAGER
999 default y if X86_VISWS
1001 Find out whether you have a PCI motherboard. PCI is the name of a
1002 bus system, i.e. the way the CPU talks to the other stuff inside
1003 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1004 VESA. If you have PCI, say Y, otherwise N.
1006 The PCI-HOWTO, available from
1007 <http://www.tldp.org/docs.html#howto>, contains valuable
1008 information about which PCI hardware does work under Linux and which
1012 prompt "PCI access mode"
1013 depends on PCI && !X86_VISWS
1016 On PCI systems, the BIOS can be used to detect the PCI devices and
1017 determine their configuration. However, some old PCI motherboards
1018 have BIOS bugs and may crash if this is done. Also, some embedded
1019 PCI-based systems don't have any BIOS at all. Linux can also try to
1020 detect the PCI hardware directly without using the BIOS.
1022 With this option, you can specify how Linux should detect the
1023 PCI devices. If you choose "BIOS", the BIOS will be used,
1024 if you choose "Direct", the BIOS won't be used, and if you
1025 choose "MMConfig", then PCI Express MMCONFIG will be used.
1026 If you choose "Any", the kernel will try MMCONFIG, then the
1027 direct access method and falls back to the BIOS if that doesn't
1028 work. If unsure, go with the default, which is "Any".
1034 config PCI_GOMMCONFIG
1041 bool "Xen PCI Frontend"
1044 The PCI device frontend driver allows the kernel to import arbitrary
1045 PCI devices from a PCI backend to support PCI driver domains.
1054 depends on !(X86_VISWS || X86_XEN) && PCI && (PCI_GOBIOS || PCI_GOANY)
1059 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1064 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1067 config XEN_PCIDEV_FRONTEND
1069 depends on PCI && X86_XEN && (PCI_GOXEN_FE || PCI_GOANY)
1072 config XEN_PCIDEV_FE_DEBUG
1073 bool "Xen PCI Frontend Debugging"
1074 depends on XEN_PCIDEV_FRONTEND
1077 Enables some debug statements within the PCI Frontend.
1079 source "drivers/pci/pcie/Kconfig"
1081 source "drivers/pci/Kconfig"
1089 depends on !(X86_VOYAGER || X86_VISWS || X86_XEN)
1091 Find out whether you have ISA slots on your motherboard. ISA is the
1092 name of a bus system, i.e. the way the CPU talks to the other stuff
1093 inside your box. Other bus systems are PCI, EISA, MicroChannel
1094 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1095 newer boards don't support it. If you have ISA, say Y, otherwise N.
1101 The Extended Industry Standard Architecture (EISA) bus was
1102 developed as an open alternative to the IBM MicroChannel bus.
1104 The EISA bus provided some of the features of the IBM MicroChannel
1105 bus while maintaining backward compatibility with cards made for
1106 the older ISA bus. The EISA bus saw limited use between 1988 and
1107 1995 when it was made obsolete by the PCI bus.
1109 Say Y here if you are building a kernel for an EISA-based machine.
1113 source "drivers/eisa/Kconfig"
1116 bool "MCA support" if !(X86_VISWS || X86_VOYAGER || X86_XEN)
1117 default y if X86_VOYAGER
1119 MicroChannel Architecture is found in some IBM PS/2 machines and
1120 laptops. It is a bus system similar to PCI or ISA. See
1121 <file:Documentation/mca.txt> (and especially the web page given
1122 there) before attempting to build an MCA bus kernel.
1124 source "drivers/mca/Kconfig"
1127 tristate "NatSemi SCx200 support"
1128 depends on !X86_VOYAGER
1130 This provides basic support for National Semiconductor's
1131 (now AMD's) Geode processors. The driver probes for the
1132 PCI-IDs of several on-chip devices, so its a good dependency
1133 for other scx200_* drivers.
1135 If compiled as a module, the driver is named scx200.
1137 config SCx200HR_TIMER
1138 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1139 depends on SCx200 && GENERIC_TIME
1142 This driver provides a clocksource built upon the on-chip
1143 27MHz high-resolution timer. Its also a workaround for
1144 NSC Geode SC-1100's buggy TSC, which loses time when the
1145 processor goes idle (as is done by the scheduler). The
1146 other workaround is idle=poll boot option.
1150 depends on AGP_AMD64
1152 source "drivers/pcmcia/Kconfig"
1154 source "drivers/pci/hotplug/Kconfig"
1158 menu "Executable file formats"
1160 source "fs/Kconfig.binfmt"
1164 source "net/Kconfig"
1166 source "drivers/Kconfig"
1170 menu "Instrumentation Support"
1171 depends on EXPERIMENTAL
1173 source "arch/i386/oprofile/Kconfig"
1176 bool "Kprobes (EXPERIMENTAL)"
1177 depends on EXPERIMENTAL && MODULES
1179 Kprobes allows you to trap at almost any kernel address and
1180 execute a callback function. register_kprobe() establishes
1181 a probepoint and specifies the callback. Kprobes is useful
1182 for kernel debugging, non-intrusive instrumentation and testing.
1183 If in doubt, say "N".
1186 source "arch/i386/Kconfig.debug"
1188 source "kernel/vserver/Kconfig"
1190 source "security/Kconfig"
1192 source "crypto/Kconfig"
1194 source "drivers/xen/Kconfig"
1196 source "lib/Kconfig"
1199 # Use the generic interrupt handling code in kernel/irq/:
1201 config GENERIC_HARDIRQS
1205 config GENERIC_IRQ_PROBE
1209 config GENERIC_PENDING_IRQ
1211 depends on GENERIC_HARDIRQS && SMP
1216 depends on SMP && !X86_VOYAGER
1221 depends on SMP && !(X86_VISWS || X86_VOYAGER || X86_XEN)
1224 config X86_BIOS_REBOOT
1226 depends on !(X86_VISWS || X86_VOYAGER)
1229 config X86_TRAMPOLINE
1231 depends on X86_SMP || (X86_VOYAGER && SMP)