[Regression, post-2.6.34] Hibernation broken on machines with radeon/KMS and r300

[Rafael J. Wysocki]

On Monday, June 14, 2010, Alex Deucher wrote:
> On Mon, Jun 14, 2010 at 10:53 AM, Rafael J. Wysocki <rjw at sisk.pl> wrote:
> > Alex, Dave,
> >
> > I'm afraid hibernation is broken on all machines using radeon/KMS with r300
> > after commit ce8f53709bf440100cb9d31b1303291551cf517f
> > (drm/radeon/kms/pm: rework power management).  At least, I'm able to reproduce
> > the symptom, which is that the machine hangs hard around the point where an
> > image is created (probably during the device thaw phase), on two different
> > boxes with r300 (the output of lspci from one of them is attached for
> > reference, the other one is HP nx6325).
> >
> > Suspend to RAM appears to work fine at least on one of the affected boxes.
> >
> > Unfortunately, the commit above changes a lot of code and it's not too easy to
> > figure out what's wrong with it and I didn't have the time to look more into
> > details of this failure.  However, it looks like you use .suspend() and
> > .resume() callbacks as .freeze() and .thaw() which may not be 100% correct
> > (in fact it looks like the "legacy" PCI suspend/resume is used, which is not
> > recommended any more).
> >
> 
> Does it work any better after Dave's last drm pull request?

Nope.  The symptom is slightly different, though, because now it hangs after
turning off the screen.

> With the latest changes, pm should not be a factor unless it's explicitly
> enabled via sysfs.

Well, I guess the first pm patch changed more than just pm, then.

Rafael