| Message ID | 5147438.NJg8nCxJVn@vostro.rjw.lan (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Rafael Wysocki |
| Headers | show |
On 05/28/2015 07:39 AM, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > The CPUIDLE_DRIVER_STATE_START symbol is defined as 1 only if > CONFIG_ARCH_HAS_CPU_RELAX is set, otherwise it is defined as 0. > However, if CONFIG_ARCH_HAS_CPU_RELAX is set, the first (index 0) > entry in the cpuidle driver's table of states is overwritten with > the default "poll" entry by the core. The "state" defined by the > "poll" entry doesn't provide ->enter_dead and ->enter_freeze > callbacks and its exit_latency is 0. > > For this reason, it is not necessary to use CPUIDLE_DRIVER_STATE_START > in cpuidle_play_dead() (->enter_dead is NULL, so the "poll state" > will be skipped by the loop). > > It also is arguably unuseful to return states with exit_latency > equal to 0 from find_deepest_state(), so the function can be modified > to start the loop from index 0 and the "poll state" will be skipped by > it as a result of the check against latency_req. > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > drivers/cpuidle/cpuidle.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > Index: linux-pm/drivers/cpuidle/cpuidle.c > =================================================================== > --- linux-pm.orig/drivers/cpuidle/cpuidle.c > +++ linux-pm/drivers/cpuidle/cpuidle.c > @@ -65,7 +65,7 @@ int cpuidle_play_dead(void) > return -ENODEV; > > /* Find lowest-power state that supports long-term idle */ > - for (i = drv->state_count - 1; i >= CPUIDLE_DRIVER_STATE_START; i--) > + for (i = drv->state_count - 1; i >= 0; i--) > if (drv->states[i].enter_dead) > return drv->states[i].enter_dead(dev, i); > > @@ -79,9 +79,9 @@ static int find_deepest_state(struct cpu > bool freeze) > { > unsigned int latency_req = 0; > - int i, ret = freeze ? -1 : CPUIDLE_DRIVER_STATE_START - 1; > + int i, ret = -ENXIO; > > - for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) { > + for (i = 0; i < drv->state_count; i++) { > struct cpuidle_state *s = &drv->states[i]; > struct cpuidle_state_usage *su = &dev->states_usage[i]; > Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Index: linux-pm/drivers/cpuidle/cpuidle.c =================================================================== --- linux-pm.orig/drivers/cpuidle/cpuidle.c +++ linux-pm/drivers/cpuidle/cpuidle.c @@ -65,7 +65,7 @@ int cpuidle_play_dead(void) return -ENODEV; /* Find lowest-power state that supports long-term idle */ - for (i = drv->state_count - 1; i >= CPUIDLE_DRIVER_STATE_START; i--) + for (i = drv->state_count - 1; i >= 0; i--) if (drv->states[i].enter_dead) return drv->states[i].enter_dead(dev, i); @@ -79,9 +79,9 @@ static int find_deepest_state(struct cpu bool freeze) { unsigned int latency_req = 0; - int i, ret = freeze ? -1 : CPUIDLE_DRIVER_STATE_START - 1; + int i, ret = -ENXIO; - for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) { + for (i = 0; i < drv->state_count; i++) { struct cpuidle_state *s = &drv->states[i]; struct cpuidle_state_usage *su = &dev->states_usage[i];