linux/Documentation/power
Kevin Hilman 02b26774af 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>
2011-08-05 21:45:20 +02:00
..
regulator
00-INDEX
apm-acpi.txt
basic-pm-debugging.txt
devices.txt
drivers-testing.txt
freezing-of-tasks.txt
interface.txt
notifiers.txt
opp.txt
pci.txt
pm_qos_interface.txt
power_supply_class.txt
runtime_pm.txt
s2ram.txt
states.txt
swsusp-and-swap-files.txt
swsusp-dmcrypt.txt
swsusp.txt
tricks.txt
userland-swsusp.txt
video.txt
video_extension.txt