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authorZhao Yakui <yakui.zhao@intel.com>2008-06-24 18:01:09 +0800
committerAndi Kleen <andi@basil.nowhere.org>2008-07-16 23:27:05 +0200
commitda5e09a1b3e5a9fc0b15a3feb64e921ccc55ba74 (patch)
tree382a75c1180e458df826ef4efbc191f3f71275c1 /include/asm-ia64
parentc1e3b377ad48febba6f91b8ae42c44ee4d4ab45e (diff)
ACPI : Create "idle=nomwait" bootparam
"idle=nomwait" disables the use of the MWAIT instruction from both C1 (C1_FFH) and deeper (C2C3_FFH) C-states. When MWAIT is unavailable, the BIOS and OS generally negotiate to use the HALT instruction for C1, and use IO accesses for deeper C-states. This option is useful for power and performance comparisons, and also to work around BIOS bugs where broken MWAIT support is advertised. http://bugzilla.kernel.org/show_bug.cgi?id=10807 http://bugzilla.kernel.org/show_bug.cgi?id=10914 Signed-off-by: Zhao Yakui <yakui.zhao@intel.com> Signed-off-by: Li Shaohua <shaohua.li@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com>
Diffstat (limited to 'include/asm-ia64')
-rw-r--r--include/asm-ia64/processor.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/asm-ia64/processor.h b/include/asm-ia64/processor.h
index f36e28a5f61e..f88fa054d01d 100644
--- a/include/asm-ia64/processor.h
+++ b/include/asm-ia64/processor.h
@@ -764,6 +764,7 @@ prefetchw (const void *x)
extern unsigned long boot_option_idle_override;
extern unsigned long idle_halt;
+extern unsigned long idle_nomwait;
#endif /* !__ASSEMBLY__ */