tree 5df2fc9b5d3fad990c6eaf187ebbe5ba7ecdb872
parent 6c81f90588972b8631bda4d538ffd0199a3e1b41
author Peter Chen <peter.chen@freescale.com> 1321390349 +0100
committer Rafael J. Wysocki <rjw@sisk.pl> 1321390349 +0100

PM / driver core: disable device's runtime PM during shutdown

There may be an issue when the user issue "reboot/shutdown" command, then
the device has shut down its hardware, after that, this runtime-pm featured
device's driver will probably be scheduled to do its suspend routine,
and at its suspend routine, it may access hardware, but the device has
already shutdown physically, then the system hang may be occurred.

I ran out this issue using an auto-suspend supported USB devices, like
3G modem, keyboard. The usb runtime suspend routine may be scheduled
after the usb controller has been shut down, and the usb runtime suspend
routine will try to suspend its roothub(controller), it will access
register, then the system hang occurs as the controller is shutdown.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Acked-by: Ming Lei <tom.leiming@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Cc: stable@kernel.org
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>