Re: [PATCH] PM: acquire device locks prior to suspending

Rafael J. Wysocki
2007-12-13T16:58:37Z

On Thursday, 13 of December 2007, Andrew Morton wrote:
> On Fri, 21 Sep 2007 15:37:40 -0400 (EDT) Alan Stern <stern@rowland.harvard.edu> wrote:
>
> > This patch (as994) reorganizes the way suspend and resume
> > notifications are sent to drivers. The major changes are that now the
> > PM core acquires every device semaphore before calling the methods,
> > and calls to device_add() during suspends will fail.
>
> Causes my t61p to deadlock during suspend-to-RAM. Really late - the little
> moon symbol has started to flash but the LCD is still powered and the
> cursor still blinks. Only a poweroff restores control.

Most probably, one of the drivers or a CPU hotplug notifier unregisters a
device during suspend (wrong).

Please boot with no_console_suspend and check if the box survives (with this
patch applied):

# echo 8 > /proc/sys/kernel/printk
# echo processors > /sys/power/pm_test
# echo mem > /sys/power/state

If it doesn't, you can try

# echo platform > /sys/power/pm_test
# echo mem > /sys/power/state

and