Re: peculiar suspend/resume bug.

[Dave Jones <davej@redhat.com>]

On Wed, Aug 16, 2006 at 10:19:59AM +1000, Nigel Cunningham wrote:
 > Hi Dave.
 > 
 > On Tue, 2006-08-15 at 18:10 -0400, Dave Jones wrote:
 > > Here's a fun one.
 > > - Get a dual core cpufreq aware laptop (Like say, a core-duo)
 > > - Add a cpufreq monitor to gnome-panel. Configure it
 > >   to watch the 2nd core.
 > > - Suspend.
 > > - Resume.
 > > 
 > > Watch the cpufreq monitor die horribly.
 > > 
 > > I believe this is because we take down the 2nd core at suspend
 > > time with cpu hotplug, and for some reason we're scheduling
 > > userspace before we bring that second core back up.
 > > 
 > > Anyone have any clues why this is happening?
 > 
 > If you hotunplug and replug the cpu using the sysfs interface, rather
 > than suspending and resuming, does the same thing happen?

cpufreq-applet crashes as soon as the cpu goes offline.
Now, the applet should be written to deal with this scenario more
gracefully, but I'm questioning whether or not userspace should
*see* the unplug/replug that suspend does at all.

IMO, when we shouldn't schedule userspace until the system is
in the exact state it was before we suspended.

		Dave

-- 
http://www.codemonkey.org.uk