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| author | Johan Hovold <johan@kernel.org> | 2017-04-10 13:38:25 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2017-04-19 23:29:18 +0200 |
| commit | bafdcde73be7d462129cecfc339d3a6abcba91d2 (patch) | |
| tree | 397c5bb357399f8d38236d9fde77ed856a2f0dac /Documentation | |
| parent | 72ec2e17f9f7f7f6082ec57183080726eb3523e3 (diff) | |
| download | linux-bafdcde73be7d462129cecfc339d3a6abcba91d2.tar.bz2 | |
PM / runtime: Document autosuspend-helper side effects
Document the fact that the autosuspend delay and enable helpers may
change the power.usage_count and resume or suspend a device depending on
the values of power.autosuspend_delay and power.use_autosuspend.
Note that this means that a driver must disable autosuspend before
disabling runtime pm on probe errors and on driver unbind if the device
is to be suspended upon return (as a negative delay may otherwise keep
the device resumed).
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/power/runtime_pm.txt | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt index 56a13b865927..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, |