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| author | Dan Murphy <dmurphy@ti.com> | 2012-02-02 14:16:57 -0600 |
|---|---|---|
| committer | Dan Murphy <dmurphy@ti.com> | 2012-02-02 14:19:13 -0600 |
| commit | 04cc23436ebc4f0caf088a97ef9404ea71acfdd1 (patch) | |
| tree | 9994f9a05d68e47e51368017288c157936e9e1cd /Documentation/power | |
| parent | 50725abe80c6893a7134977c8b576a0ec4eef5a5 (diff) | |
| parent | 235eae6e5e402f5f723203e4444f10c16c7c3be3 (diff) | |
| download | kernel_samsung_espresso10-04cc23436ebc4f0caf088a97ef9404ea71acfdd1.zip kernel_samsung_espresso10-04cc23436ebc4f0caf088a97ef9404ea71acfdd1.tar.gz kernel_samsung_espresso10-04cc23436ebc4f0caf088a97ef9404ea71acfdd1.tar.bz2 | |
Merge branch 'linux-3.0.18' into p-android-omap-3.0
Conflicts:
arch/arm/mach-omap2/smartreflex.c
drivers/i2c/busses/i2c-omap.c
drivers/usb/host/ehci.h
drivers/usb/musb/musb_core.c
fs/proc/base.c
Signed-off-by: Dan Murphy <dmurphy@ti.com>
Diffstat (limited to 'Documentation/power')
| -rw-r--r-- | Documentation/power/runtime_pm.txt | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt index 22852b3..a6b3430 100644 --- a/Documentation/power/runtime_pm.txt +++ b/Documentation/power/runtime_pm.txt @@ -709,6 +709,16 @@ 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. +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 +autosuspend delay time has expired. If the ->runtime_suspend() callback +returns -EAGAIN or -EBUSY, and if the next autosuspend delay expiration time is +in the future (as it normally would be if the callback invoked +pm_runtime_mark_last_busy()), the PM core will automatically reschedule the +autosuspend. The ->runtime_suspend() callback can't do this rescheduling +itself because no suspend requests of any kind are accepted while the device is +suspending (i.e., while the callback is running). + The implementation is well suited for asynchronous use in interrupt contexts. However such use inevitably involves races, because the PM core can't synchronize ->runtime_suspend() callbacks with the arrival of I/O requests. |