PM / Sleep: avoid 'autosleep' in shutdown progress
Prevent automatic system suspend from happening during system
shutdown by making try_to_suspend() check system_state and return
immediately if it is not SYSTEM_RUNNING.
This prevents the following breakage from happening (scenario from
Zhang Yanmin):
Kernel starts shutdown and calls all device driver's shutdown
callback. When a driver's shutdown is called, the last wakelock is
released and suspend-to-ram starts. However, as some driver's shut
down callbacks already shut down devices and disabled runtime pm,
the suspend-to-ram calls driver's suspend callback without noticing
that device is already off and causes crash.
[rjw: Changelog] Signed-off-by: Liu ShuoX <shuox.liu@intel.com> Cc: 3.5+ <stable@vger.kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>