From c1e3b377ad48febba6f91b8ae42c44ee4d4ab45e Mon Sep 17 00:00:00 2001 From: Zhao Yakui Date: Tue, 24 Jun 2008 17:58:53 +0800 Subject: ACPI: Create "idle=halt" bootparam "idle=halt" limits the idle loop to using the halt instruction. No MWAIT, no IO accesses, no C-states deeper than C1. If something is broken in the idle code, "idle=halt" is a less severe workaround than "idle=poll" which disables all power savings. Signed-off-by: Zhao Yakui Signed-off-by: Len Brown Signed-off-by: Andi Kleen --- include/asm-ia64/processor.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/asm-ia64/processor.h') diff --git a/include/asm-ia64/processor.h b/include/asm-ia64/processor.h index 6aff126fc07e..f36e28a5f61e 100644 --- a/include/asm-ia64/processor.h +++ b/include/asm-ia64/processor.h @@ -763,6 +763,7 @@ prefetchw (const void *x) #define spin_lock_prefetch(x) prefetchw(x) extern unsigned long boot_option_idle_override; +extern unsigned long idle_halt; #endif /* !__ASSEMBLY__ */ -- cgit v1.2.2 From da5e09a1b3e5a9fc0b15a3feb64e921ccc55ba74 Mon Sep 17 00:00:00 2001 From: Zhao Yakui Date: Tue, 24 Jun 2008 18:01:09 +0800 Subject: 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 Signed-off-by: Li Shaohua Signed-off-by: Len Brown Signed-off-by: Andi Kleen --- include/asm-ia64/processor.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/asm-ia64/processor.h') 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__ */ -- cgit v1.2.2