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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 /arch/ia64/kernel
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 'arch/ia64/kernel')
-rw-r--r--arch/ia64/kernel/process.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 612b3c4a060..3ab8373103e 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -57,6 +57,8 @@ unsigned long boot_option_idle_override = 0;
EXPORT_SYMBOL(boot_option_idle_override);
unsigned long idle_halt;
EXPORT_SYMBOL(idle_halt);
+unsigned long idle_nomwait;
+EXPORT_SYMBOL(idle_nomwait);
void
ia64_do_show_stack (struct unw_frame_info *info, void *arg)