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

[Rafael J. Wysocki]

On Tuesday, June 15, 2010, Rafael J. Wysocki wrote:
> On Monday, June 14, 2010, Alex Deucher wrote:
> > On Mon, Jun 14, 2010 at 3:03 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> > > On Monday, June 14, 2010, Alex Deucher wrote:
> > >> On Mon, Jun 14, 2010 at 10:53 AM, Rafael J. Wysocki <rjw@xxxxxxx> 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.
> > 
> > Does this patch help?
> > http://lists.freedesktop.org/archives/dri-devel/2010-June/001314.html
> 
> No, it doesn't.  I try to hibernate, everything works to the point where the
> screen goes off and the box hangs (solid).  Normally, it would turn the
> screen back on and continue with saving the image.
> 
> But, since that happens with the patch above applied, I think it doesn't
> really pass the suspend phase (IOW, it probably hangs somewhere in the radeon's
> suspend routine).

I've just verified that in fact hibernation works on HP nx6325 with 2.6.35-rc3,
but it takes about 55 sec. to suspend the graphics adapter in the "freeze"
phase.  Surprisingly enough, during suspend to RAM it works normally
(as well as in the "poweroff" phase of hibernation).

Rafael
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