diff options
| author | Kevin Hilman <khilman@ti.com> | 2011-08-05 21:45:20 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki <rjw@sisk.pl> | 2011-08-05 21:45:20 +0200 |
| commit | 02b26774afebb2d62695ba3230319d70d8c6cc2d (patch) | |
| tree | 956c4056fcb42d2c2b2a75e20d3ad98f148865fc /Documentation/power | |
| parent | fe202fde50a986a8510c62a76dc8733c1a8fac86 (diff) | |
PM / Runtime: Allow _put_sync() from interrupts-disabled context
Currently the use of pm_runtime_put_sync() is not safe from
interrupts-disabled context because rpm_idle() will release the
spinlock and enable interrupts for the idle callbacks. This enables
interrupts during a time where interrupts were expected to be
disabled, and can have strange side effects on drivers that expected
interrupts to be disabled.
This is not a bug since the documentation clearly states that only
_put_sync_suspend() is safe in IRQ-safe mode.
However, pm_runtime_put_sync() could be made safe when in IRQ-safe
mode by releasing the spinlock but not re-enabling interrupts, which
is what this patch aims to do.
Problem was found when using some buggy drivers that set
pm_runtime_irq_safe() and used _put_sync() in interrupts-disabled
context.
Reported-by: Colin Cross <ccross@google.com>
Tested-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Diffstat (limited to 'Documentation/power')
| -rw-r--r-- | Documentation/power/runtime_pm.txt | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt index 14dd3c6ad97e..4ce5450ab6e8 100644 --- a/Documentation/power/runtime_pm.txt +++ b/Documentation/power/runtime_pm.txt @@ -54,11 +54,10 @@ referred to as subsystem-level callbacks in what follows. By default, the callbacks are always invoked in process context with interrupts enabled. However, subsystems can use the pm_runtime_irq_safe() helper function to tell the PM core that a device's ->runtime_suspend() and ->runtime_resume() -callbacks should be invoked in atomic context with interrupts disabled -(->runtime_idle() is still invoked the default way). This implies that these -callback routines must not block or sleep, but it also means that the -synchronous helper functions listed at the end of Section 4 can be used within -an interrupt handler or in an atomic context. +callbacks should be invoked in atomic context with interrupts disabled. +This implies that these callback routines must not block or sleep, but it also +means that the synchronous helper functions listed at the end of Section 4 can +be used within an interrupt handler or in an atomic context. The subsystem-level suspend callback is _entirely_ _responsible_ for handling the suspend of the device as appropriate, which may, but need not include @@ -483,6 +482,7 @@ pm_runtime_suspend() pm_runtime_autosuspend() pm_runtime_resume() pm_runtime_get_sync() +pm_runtime_put_sync() pm_runtime_put_sync_suspend() 5. Runtime PM Initialization, Device Probing and Removal |