diff options
Diffstat (limited to 'Documentation/power/runtime_pm.rst')
| -rw-r--r-- | Documentation/power/runtime_pm.rst | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/Documentation/power/runtime_pm.rst b/Documentation/power/runtime_pm.rst index 65b86e487a..5c4e730f38 100644 --- a/Documentation/power/runtime_pm.rst +++ b/Documentation/power/runtime_pm.rst @@ -154,7 +154,7 @@ suspending the device are satisfied) and to queue up a suspend request for the device in that case. If there is no idle callback, or if the callback returns 0, then the PM core will attempt to carry out a runtime suspend of the device, also respecting devices configured for autosuspend. In essence this means a -call to pm_runtime_autosuspend() (do note that drivers needs to update the +call to __pm_runtime_autosuspend() (do note that drivers needs to update the device last busy mark, pm_runtime_mark_last_busy(), to control the delay under this circumstance). To prevent this (for example, if the callback routine has started a delayed suspend), the routine must return a non-zero value. Negative @@ -396,10 +396,9 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h: nonzero, increment the counter and return 1; otherwise return 0 without changing the counter - `int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count);` + `int pm_runtime_get_if_active(struct device *dev);` - return -EINVAL if 'power.disable_depth' is nonzero; otherwise, if the - runtime PM status is RPM_ACTIVE, and either ign_usage_count is true - or the device's usage_count is non-zero, increment the counter and + runtime PM status is RPM_ACTIVE, increment the counter and return 1; otherwise return 0 without changing the counter `void pm_runtime_put_noidle(struct device *dev);` @@ -410,6 +409,10 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h: pm_request_idle(dev) and return its result `int pm_runtime_put_autosuspend(struct device *dev);` + - does the same as __pm_runtime_put_autosuspend() for now, but in the + future, will also call pm_runtime_mark_last_busy() as well, DO NOT USE! + + `int __pm_runtime_put_autosuspend(struct device *dev);` - decrement the device's usage counter; if the result is 0 then run pm_request_autosuspend(dev) and return its result @@ -540,6 +543,7 @@ It is safe to execute the following helper functions from interrupt context: - pm_runtime_put_noidle() - pm_runtime_put() - pm_runtime_put_autosuspend() +- __pm_runtime_put_autosuspend() - pm_runtime_enable() - pm_suspend_ignore_children() - pm_runtime_set_active() @@ -730,6 +734,7 @@ out the following operations: for it, respectively. 7. Generic subsystem callbacks +============================== Subsystems may wish to conserve code space by using the set of generic power management callbacks provided by the PM core, defined in @@ -865,9 +870,9 @@ automatically be delayed until the desired period of inactivity has elapsed. Inactivity is determined based on the power.last_busy field. Drivers should call pm_runtime_mark_last_busy() to update this field after carrying out I/O, -typically just before calling pm_runtime_put_autosuspend(). The desired length -of the inactivity period is a matter of policy. Subsystems can set this length -initially by calling pm_runtime_set_autosuspend_delay(), but after device +typically just before calling __pm_runtime_put_autosuspend(). The desired +length of the inactivity period is a matter of policy. Subsystems can set this +length initially by calling pm_runtime_set_autosuspend_delay(), but after device registration the length should be controlled by user space, using the /sys/devices/.../power/autosuspend_delay_ms attribute. @@ -878,7 +883,7 @@ instead of the non-autosuspend counterparts:: Instead of: pm_runtime_suspend use: pm_runtime_autosuspend; Instead of: pm_schedule_suspend use: pm_request_autosuspend; - Instead of: pm_runtime_put use: pm_runtime_put_autosuspend; + Instead of: pm_runtime_put use: __pm_runtime_put_autosuspend; Instead of: pm_runtime_put_sync use: pm_runtime_put_sync_autosuspend. Drivers may also continue to use the non-autosuspend helper functions; they @@ -917,7 +922,7 @@ Here is a schematic pseudo-code example:: lock(&foo->private_lock); if (--foo->num_pending_requests == 0) { pm_runtime_mark_last_busy(&foo->dev); - pm_runtime_put_autosuspend(&foo->dev); + __pm_runtime_put_autosuspend(&foo->dev); } else { foo_process_next_request(foo); } |