diff options
| -rw-r--r-- | Documentation/kernel-parameters.txt | 4 | ||||
| -rw-r--r-- | arch/ia64/kernel/process.c | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/process.c | 17 | ||||
| -rw-r--r-- | drivers/acpi/processor_idle.c | 22 | ||||
| -rw-r--r-- | include/asm-ia64/processor.h | 1 | ||||
| -rw-r--r-- | include/asm-x86/processor.h | 1 |
6 files changed, 45 insertions, 2 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 312fe77..65db7f4 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -818,7 +818,7 @@ and is between 256 and 4096 characters. It is defined in the file See Documentation/ide/ide.txt. idle= [X86] - Format: idle=poll or idle=mwait + Format: idle=poll or idle=mwait, idle=halt 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. @@ -826,6 +826,8 @@ and is between 256 and 4096 characters. It is defined in the file to not use it because it doesn't save as much power as a normal idle loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same as idle=poll. + idle=halt. Halt is forced to be used for CPU idle. + In such case C2/C3 won't be used again. ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem Claim all unknown PCI IDE storage controllers. diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c index fabaf08..612b3c4 100644 --- a/arch/ia64/kernel/process.c +++ b/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_halt; +EXPORT_SYMBOL(idle_halt); void ia64_do_show_stack (struct unw_frame_info *info, void *arg) diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 7dceea9..7fc7294 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -7,6 +7,10 @@ #include <linux/module.h> #include <linux/pm.h> #include <linux/clockchips.h> +#include <asm/system.h> + +unsigned long idle_halt; +EXPORT_SYMBOL(idle_halt); struct kmem_cache *task_xstate_cachep; @@ -325,7 +329,18 @@ static int __init idle_setup(char *str) pm_idle = poll_idle; } else if (!strcmp(str, "mwait")) force_mwait = 1; - else + else if (!strcmp(str, "halt")) { + /* + * When the boot option of idle=halt is added, halt is + * forced to be used for CPU idle. In such case CPU C2/C3 + * won't be used again. + * To continue to load the CPU idle driver, don't touch + * the boot_option_idle_override. + */ + pm_idle = default_idle; + idle_halt = 1; + return 0; + } else return -1; boot_option_idle_override = 1; diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 0fc310e..c75c7ac 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -41,6 +41,7 @@ #include <linux/pm_qos_params.h> #include <linux/clockchips.h> #include <linux/cpuidle.h> +#include <linux/cpuidle.h> /* * Include the apic definitions for x86 to have the APIC timer related defines @@ -57,6 +58,7 @@ #include <acpi/acpi_bus.h> #include <acpi/processor.h> +#include <asm/processor.h> #define ACPI_PROCESSOR_COMPONENT 0x01000000 #define ACPI_PROCESSOR_CLASS "processor" @@ -955,6 +957,17 @@ static int acpi_processor_get_power_info_cst(struct acpi_processor *pr) } else { continue; } + if (cx.type == ACPI_STATE_C1 && idle_halt) { + /* + * In most cases the C1 space_id obtained from + * _CST object is FIXED_HARDWARE access mode. + * But when the option of idle=halt is added, + * the entry_method type should be changed from + * CSTATE_FFH to CSTATE_HALT. + */ + cx.entry_method = ACPI_CSTATE_HALT; + snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT"); + } } else { snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI IOPORT 0x%x", cx.address); @@ -1780,6 +1793,15 @@ int __cpuinit acpi_processor_power_init(struct acpi_processor *pr, return 0; if (!first_run) { + if (idle_halt) { + /* + * When the boot option of "idle=halt" is added, halt + * is used for CPU IDLE. + * In such case C2/C3 is meaningless. So the max_cstate + * is set to one. + */ + max_cstate = 1; + } dmi_check_system(processor_power_dmi_table); max_cstate = acpi_processor_cstate_check(max_cstate); if (max_cstate < ACPI_C_STATES_MAX) diff --git a/include/asm-ia64/processor.h b/include/asm-ia64/processor.h index 6aff126..f36e28a 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__ */ diff --git a/include/asm-x86/processor.h b/include/asm-x86/processor.h index 7f73827..bc22162 100644 --- a/include/asm-x86/processor.h +++ b/include/asm-x86/processor.h @@ -727,6 +727,7 @@ 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_halt; extern void enable_sep_cpu(void); extern int sysenter_setup(void); |