diff options
Diffstat (limited to 'Documentation/power/runtime_pm.txt')
| -rw-r--r-- | Documentation/power/runtime_pm.txt | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt index 64546eb9a16a..ee69d7532172 100644 --- a/Documentation/power/runtime_pm.txt +++ b/Documentation/power/runtime_pm.txt @@ -478,15 +478,23 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h: - set the power.last_busy field to the current time void pm_runtime_use_autosuspend(struct device *dev); - - set the power.use_autosuspend flag, enabling autosuspend delays + - set the power.use_autosuspend flag, enabling autosuspend delays; call + pm_runtime_get_sync if the flag was previously cleared and + power.autosuspend_delay is negative void pm_runtime_dont_use_autosuspend(struct device *dev); - - clear the power.use_autosuspend flag, disabling autosuspend delays + - clear the power.use_autosuspend flag, disabling autosuspend delays; + decrement the device's usage counter if the flag was previously set and + power.autosuspend_delay is negative; call pm_runtime_idle void pm_runtime_set_autosuspend_delay(struct device *dev, int delay); - set the power.autosuspend_delay value to 'delay' (expressed in milliseconds); if 'delay' is negative then runtime suspends are - prevented + prevented; if power.use_autosuspend is set, pm_runtime_get_sync may be + called or the device's usage counter may be decremented and + pm_runtime_idle called depending on if power.autosuspend_delay is + changed to or from a negative value; if power.use_autosuspend is clear, + pm_runtime_idle is called unsigned long pm_runtime_autosuspend_expiration(struct device *dev); - calculate the time when the current autosuspend delay period will expire, @@ -836,9 +844,8 @@ of the non-autosuspend counterparts: Instead of: pm_runtime_put_sync use: pm_runtime_put_sync_autosuspend. Drivers may also continue to use the non-autosuspend helper functions; they -will behave normally, not taking the autosuspend delay into account. -Similarly, if the power.use_autosuspend field isn't set then the autosuspend -helper functions will behave just like the non-autosuspend counterparts. +will behave normally, which means sometimes taking the autosuspend delay into +account (see pm_runtime_idle). Under some circumstances a driver or subsystem may want to prevent a device from autosuspending immediately, even though the usage counter is zero and the |