path: root/Documentation
diff options
authorLen Brown <len.brown@intel.com>2007-08-16 03:34:22 -0400
committerLen Brown <len.brown@intel.com>2007-08-21 00:33:35 -0400
commit61ec7567db103d537329b0db9a887db570431ff4 (patch)
tree7287eb4bd00c09434fc2dd0babadfd0eb7ddc832 /Documentation
parent28e8351ac22de25034e048c680014ad824323c65 (diff)
ACPI: boot correctly with "nosmp" or "maxcpus=0"
In MPS mode, "nosmp" and "maxcpus=0" boot a UP kernel with IOAPIC disabled. However, in ACPI mode, these parameters didn't completely disable the IO APIC initialization code and boot failed. init/main.c: Disable the IO_APIC if "nosmp" or "maxcpus=0" undefine disable_ioapic_setup() when it doesn't apply. i386: delete ioapic_setup(), it was a duplicate of parse_noapic() delete undefinition of disable_ioapic_setup() x86_64: rename disable_ioapic_setup() to parse_noapic() to match i386 define disable_ioapic_setup() in header to match i386 http://bugzilla.kernel.org/show_bug.cgi?id=1641 Acked-by: Andi Kleen <ak@suse.de> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'Documentation')
1 files changed, 6 insertions, 9 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 975f029be25..17770b45631 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -952,14 +952,10 @@ and is between 256 and 4096 characters. It is defined in the file
Format: <1-256>
maxcpus= [SMP] Maximum number of processors that an SMP kernel
- should make use of.
- Using "nosmp" or "maxcpus=0" will disable SMP
- entirely (the MPS table probe still happens, though).
- A command-line option of "maxcpus=<NUM>", where <NUM>
- is an integer greater than 0, limits the maximum number
- of CPUs activated in SMP mode to <NUM>.
- Using "maxcpus=1" on an SMP kernel is the trivial
- case of an SMP kernel with only one CPU.
+ should make use of. maxcpus=n : n >= 0 limits the
+ kernel to using 'n' processors. n=0 is a special case,
+ it is equivalent to "nosmp", which also disables
+ the IO APIC.
max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
equal to this physical address is ignored.
@@ -1184,7 +1180,8 @@ and is between 256 and 4096 characters. It is defined in the file
nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
- nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
+ nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
+ and disable the IO APIC. legacy for "maxcpus=0".
nosoftlockup [KNL] Disable the soft-lockup detector.