On 2014/5/5 6:51, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wyso...@intel.com> > > If freeze_enter() is called, we want to bypass the current cpuidle > governor and always use the deepest available (that is, not disabled) > C-state, because we want to save as much energy as reasonably possible > then and runtime latency constraints don't matter at that point, since > the system is in a sleep state anyway. > > Signed-off-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com> > --- > > This is on top of https://patchwork.kernel.org/patch/4071541/ . > > --- > drivers/cpuidle/cpuidle.c | 45 > ++++++++++++++++++++++++++++++++++++++++++++- > include/linux/cpuidle.h | 2 ++ > kernel/power/suspend.c | 2 ++ > 3 files changed, 48 insertions(+), 1 deletion(-) > > Index: linux-pm/drivers/cpuidle/cpuidle.c > =================================================================== > --- linux-pm.orig/drivers/cpuidle/cpuidle.c > +++ linux-pm/drivers/cpuidle/cpuidle.c > @@ -32,6 +32,7 @@ LIST_HEAD(cpuidle_detected_devices); > static int enabled_devices; > static int off __read_mostly; > static int initialized __read_mostly; > +static bool use_deepest_state __read_mostly; > > int cpuidle_disabled(void) > { > @@ -65,6 +66,45 @@ int cpuidle_play_dead(void) > } > > /** > + * cpuidle_use_deepest_state - Enable/disable the "deepest idle" mode. > + * @enable: Whether enable or disable the feature. > + * > + * If the "deepest idle" mode is enabled, cpuidle will ignore the governor > and > + * always use the state with the greatest exit latency (out of the states > that > + * are not disabled). > + * > + * This function can only be called after cpuidle_pause() to avoid races. > + */ > +void cpuidle_use_deepest_state(bool enable) > +{ > + use_deepest_state = enable; > +} > + > +/** > + * cpuidle_find_deepest_state - Find the state of the greatest exit latency. > + * @drv: cpuidle driver for a given CPU. > + * @dev: cpuidle device for a given CPU. > + */ > +static int cpuidle_find_deepest_state(struct cpuidle_driver *drv, > + struct cpuidle_device *dev) > +{ > + unsigned int latency_req = 0; > + int i, ret = CPUIDLE_DRIVER_STATE_START - 1; > + > + for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) { > + struct cpuidle_state *s = &drv->states[i]; > + struct cpuidle_state_usage *su = &dev->states_usage[i]; > + > + if (s->disabled || su->disable || s->exit_latency <= > latency_req) > + continue; > + > + latency_req = s->exit_latency; > + ret = i; > + } > + return ret; > +} > + > +/** > * cpuidle_enter_state - enter the state and update stats > * @dev: cpuidle device for this cpu > * @drv: cpuidle driver for this cpu > @@ -124,6 +164,9 @@ int cpuidle_select(struct cpuidle_driver > if (!drv || !dev || !dev->enabled) > return -EBUSY; > > + if (unlikely(use_deepest_state)) > + return cpuidle_find_deepest_state(drv, dev); > + > return cpuidle_curr_governor->select(drv, dev); > } > > @@ -155,7 +198,7 @@ int cpuidle_enter(struct cpuidle_driver > */ > void cpuidle_reflect(struct cpuidle_device *dev, int index) > { > - if (cpuidle_curr_governor->reflect) > + if (cpuidle_curr_governor->reflect && !unlikely(use_deepest_state)) > cpuidle_curr_governor->reflect(dev, index); > } > > Index: linux-pm/include/linux/cpuidle.h > =================================================================== > --- linux-pm.orig/include/linux/cpuidle.h > +++ linux-pm/include/linux/cpuidle.h > @@ -143,6 +143,7 @@ extern void cpuidle_resume(void); > extern int cpuidle_enable_device(struct cpuidle_device *dev); > extern void cpuidle_disable_device(struct cpuidle_device *dev); > extern int cpuidle_play_dead(void); > +extern void cpuidle_use_deepest_state(bool enable); > > extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device > *dev); > #else > @@ -175,6 +176,7 @@ static inline int cpuidle_enable_device( > {return -ENODEV; } > static inline void cpuidle_disable_device(struct cpuidle_device *dev) { } > static inline int cpuidle_play_dead(void) {return -ENODEV; } > +static inline void cpuidle_use_deepest_state(bool enable) {} > static inline struct cpuidle_driver *cpuidle_get_cpu_driver( > struct cpuidle_device *dev) {return NULL; } > #endif > Index: linux-pm/kernel/power/suspend.c > =================================================================== > --- linux-pm.orig/kernel/power/suspend.c > +++ linux-pm/kernel/power/suspend.c > @@ -54,9 +54,11 @@ static void freeze_begin(void) > > static void freeze_enter(void) > { > + cpuidle_use_deepest_state(true); > cpuidle_resume(); > wait_event(suspend_freeze_wait_head, suspend_freeze_wake); > cpuidle_pause(); > + cpuidle_use_deepest_state(false); > } > > void freeze_wake(void) >
Tested-by: Aubrey Li <aubrey...@linux.intel.com> I tested freeze mode on ASUS-T100, it works as expected. Thanks Rafael! -Aubrey -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
