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

[Andrew Morton <akpm@linux-foundation.org>]

On Thu, 13 Dec 2007 11:02:36 -0500 (EST)
Alan Stern <stern@rowland.harvard.edu> wrote:

> On Wed, 12 Dec 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.
> 
> Is there any chance of debugging this?

Spose so, although debugging 2.6.24-rc5 regressions seems a more useful way
to spend one's time.

>  You have removed the patch from 
> the current -mm source.  Does anybody else report a similar problem?
> 
> Proper debugging would require, to begin with, enabling 
> CONFIG_PM_VERBOSE and booting with no_console_suspend.

Will try to remember to take a look this evening.

Speaking of efficient use of resources: how many other people have tested
suspend-to-disk with this patch applied?  And on how many machines?