applied. (found it:-) thanks, -Len On Tue, 17 Jun 2008, Zhao Yakui wrote: > Subject:[ACPI]:Add boot option of "idle=nomwait" to disable mwait for CPU C-states > From: Zhao Yakui <yakui.zhao@xxxxxxxxx> > > Add the boot option of "idle=nomwait" to disable Mwait for CPU C-states. > If the boot option of "idle=nomwait" is added , OSPM should not > use mwait for cpu idle even when the mwait is supported. In such case the > C2C3_FFH access mode will be disabled. > > http://bugzilla.kernel.org/show_bug.cgi?id=10807 > > Signed-off-by: Zhao Yakui <yakui.zhao@xxxxxxxxx> > Signed-off-by: Li Shaohua <shaohua.li@xxxxxxxxx> > --- > Documentation/kernel-parameters.txt | 4 +++- > arch/ia64/kernel/process.c | 2 ++ > arch/x86/kernel/process.c | 14 ++++++++++++++ > drivers/acpi/processor_core.c | 12 ++++++++++++ > include/asm-ia64/processor.h | 1 + > include/asm-x86/processor.h | 1 + > 6 files changed, 33 insertions(+), 1 deletion(-) > > Index: linux-2.6/Documentation/kernel-parameters.txt > =================================================================== > --- linux-2.6.orig/Documentation/kernel-parameters.txt > +++ linux-2.6/Documentation/kernel-parameters.txt > @@ -785,7 +785,7 @@ and is between 256 and 4096 characters. > See Documentation/ide/ide.txt. > > idle= [X86] > - Format: idle=poll or idle=mwait, idle = halt > + Format: idle=poll or idle=mwait, idle = halt, idle=nomwait > Poll forces a polling idle loop that can slightly improves the performance > of waking up a idle CPU, but will use a lot of power and make the system > run hot. Not recommended. > @@ -795,6 +795,8 @@ and is between 256 and 4096 characters. > as idle=poll. > idle = halt . Halt is forced to be used for CPU idle. > In such case C2/C3 won't be used again. > + idle = nomwait. disable Mwait for CPU C-state. > + In such case C2C3_FFH access mode will be disabled. > > ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem > Claim all unknown PCI IDE storage controllers. > Index: linux-2.6/arch/ia64/kernel/process.c > =================================================================== > --- linux-2.6.orig/arch/ia64/kernel/process.c > +++ linux-2.6/arch/ia64/kernel/process.c > @@ -55,6 +55,8 @@ void (*ia64_mark_idle)(int); > > unsigned long boot_option_idle_override = 0; > EXPORT_SYMBOL(boot_option_idle_override); > +unsigned long idle_nomwait; > +EXPORT_SYMBOL(idle_nomwait); > > void > ia64_do_show_stack (struct unw_frame_info *info, void *arg) > Index: linux-2.6/arch/x86/kernel/process.c > =================================================================== > --- linux-2.6.orig/arch/x86/kernel/process.c > +++ linux-2.6/arch/x86/kernel/process.c > @@ -7,6 +7,10 @@ > #include <linux/module.h> > #include <linux/pm.h> > #include <asm/system.h> > +#include <asm/processor.h> > + > +unsigned long idle_nomwait; > +EXPORT_SYMBOL(idle_nomwait); > > struct kmem_cache *task_xstate_cachep; > > @@ -172,6 +176,16 @@ static int __init idle_setup(char *str) > force_mwait = 1; > else if (!strcmp(str, "halt")) > pm_idle = default_idle; > + else if (!strcmp(str, "nomwait")) { > + /* > + * If the boot option of "idle=nomwait" is added, > + * it means that mwait will be disabled for CPU C2/C3 > + * states. In such case it won't touch the variable > + * of boot_option_idle_override. > + */ > + idle_nomwait = 1; > + return 0; > + } > else > return -1; > > Index: linux-2.6/include/asm-ia64/processor.h > =================================================================== > --- linux-2.6.orig/include/asm-ia64/processor.h > +++ linux-2.6/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_nomwait; > > #endif /* !__ASSEMBLY__ */ > > Index: linux-2.6/include/asm-x86/processor.h > =================================================================== > --- linux-2.6.orig/include/asm-x86/processor.h > +++ linux-2.6/include/asm-x86/processor.h > @@ -732,6 +732,7 @@ extern int force_mwait; > extern void select_idle_routine(const struct cpuinfo_x86 *c); > > extern unsigned long boot_option_idle_override; > +extern unsigned long idle_nomwait; > > extern void enable_sep_cpu(void); > extern int sysenter_setup(void); > Index: linux-2.6/drivers/acpi/processor_core.c > =================================================================== > --- linux-2.6.orig/drivers/acpi/processor_core.c > +++ linux-2.6/drivers/acpi/processor_core.c > @@ -267,6 +267,18 @@ static int acpi_processor_set_pdc(struct > if (!pdc_in) > return status; > > + if (idle_nomwait) { > + /* > + * If mwait is disabled for CPU C-states, the C2C3_FFH access > + * mode will be disabled in the parameter of _PDC object. > + */ > + union acpi_object *obj; > + u32 *buffer = NULL; > + > + obj = pdc_in->pointer; > + buffer = (u32 *)(obj->buffer.pointer); > + buffer[2] &= ~(ACPI_PDC_C_C2C3_FFH); > + } > status = acpi_evaluate_object(pr->handle, "_PDC", pdc_in, NULL); > > if (ACPI_FAILURE(status)) > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
