Re: [Nouveau] [regression drm/noveau] suspend to ram -> BOOM: exception RIP: drm_calc_vbltimestamp_from_scanoutpos+335

[Tobias Klausmann]

The conversion is a nice catch, but i'd like to have a bit more context, 
see below!

With a better description:

Tobias Klausmann <tobias.johannes.klausmann@xxxxxxxxxx>


On 7/14/17 5:10 PM, Karol Herbst wrote:
> Yeah, we shouldn't let the machine die. Are there more WARN_ON_ONCE
> usage we could convert to WARN_ONCE?
>
> Reviewed-By: Karol Herbst <karolherbst@xxxxxxxxx>
>
> On Fri, Jul 14, 2017 at 5:05 PM, Tobias Klausmann
> <tobias.johannes.klausmann@xxxxxxxxxx> wrote:
> > On 7/14/17 3:41 PM, Mike Galbraith wrote:
> > > On Fri, 2017-07-14 at 15:36 +0200, Mike Galbraith wrote:
> > > >    All DRM did was to slip a
> > > > WARN_ON_ONCE() that nouveau triggers into a kernel module where such
> > > > things no longer warn, they blow the box out of the water.
> > > BTW, turn that irksome WARN_ON_ONCE() in drivers/gpu/drm/drm_vblank.c
> > > into a WARN_ONCE(), and all is peachy, you get the warning, box lives.
> > >
> > > ---
> > >    drivers/gpu/drm/drm_vblank.c |    3 ++-
> > >    1 file changed, 2 insertions(+), 1 deletion(-)
> > >
> > > --- a/drivers/gpu/drm/drm_vblank.c
> > > +++ b/drivers/gpu/drm/drm_vblank.c
> > > @@ -605,7 +605,8 @@ bool drm_calc_vbltimestamp_from_scanoutp
> > >           */
> > >          if (mode->crtc_clock == 0) {
> > >                  DRM_DEBUG("crtc %u: Noop due to uninitialized mode.\n",
> > > pipe);
> > > -               WARN_ON_ONCE(drm_drv_uses_atomic_modeset(dev));
> > > +               WARN_ONCE(drm_drv_uses_atomic_modeset(dev), "%s: report
> > > me.\n",

"report me" seems a bit odd, maybe just uninitialized mode?


> > > +                         dev->driver->name);
> > >                  return false;
> > >          }
> >
> >
> > Hey,
> >
> > confirmed this helps saving the box, but we still have to find the root
> > cause! Backtrace with the above fix applied (and the one which came in with
> > the latest drm-fixes merge)!
> >
> >
> > [1] https://hastebin.com/uyoqifijed.http
> >
> > Thanks,
> >
> > Tobias
> > Reviewed-By: Karol Herbst <karolherbst@xxxxxxxxx>
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