PM: Fix potential issue with failing asynchronous suspend
authorRafael J. Wysocki <rjw@sisk.pl>
Wed, 22 Sep 2010 20:10:57 +0000 (22:10 +0200)
committerRafael J. Wysocki <rjw@sisk.pl>
Sat, 16 Oct 2010 23:57:43 +0000 (01:57 +0200)
commit098dff738abbeaea15fc95c4f4fdaee1e9bbea75
treeb2282f59358b4f1e8bbf9949ff1eec4c8016ca5f
parent074037ec79bea73edf1b1ec72fef1010e83e3cc5
PM: Fix potential issue with failing asynchronous suspend

There is a potential issue with the asynchronous suspend code that
a device driver suspending asynchronously may not notice that it
should back off.  There are two failing scenarions, (1) when the
driver is waiting for a driver suspending synchronously to complete
and that second driver returns error code, in which case async_error
won't be set and the waiting driver will continue suspending and (2)
after the driver has called device_pm_wait_for_dev() and the waited
for driver returns error code, in which case the caller of
device_pm_wait_for_dev() will not know that there was an error and
will continue suspending.

To fix this issue make __device_suspend() set async_error, so
async_suspend() doesn't need to set it any more, and make
device_pm_wait_for_dev() return async_error, so that its callers
can check whether or not they should continue suspending.

No more changes are necessary, since device_pm_wait_for_dev() is
not used by any drivers' suspend routines.

Reported-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/base/power/main.c
include/linux/pm.h