[Intel-gfx] [PATCH] drm/i915: Fix divide by zero on watermark update

[Daniel Vetter]

On Thu, Jul 16, 2015 at 01:43:15PM -0300, Paulo Zanoni wrote:
> 2015-07-16 13:36 GMT-03:00 Mika Kuoppala <mika.kuoppala at linux.intel.com>:
> > Fix divide by zero if we end up updating the watermarks
> > with zero dotclock.
> >
> > This is a stop gap measure to allow module load in cases
> > where our state keeping fails.
> >
> > v2: WARN_ON added (Paulo)
> 
> Since we're not hiding the problem (due to the WARN_ON) and the patch
> improves the current situation:
> Reviewed-by: Paulo Zanoni <paulo.r.zanoni at intel.com>

Queued for -next, thanks for the patch.
-Daniel

> 
> >
> > Cc: Paulo Zanoni <przanoni at gmail.com>
> > Cc: Damien Lespiau <damien.lespiau at intel.com>
> > Signed-off-by: Mika Kuoppala <mika.kuoppala at intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_pm.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > index 5eeddc9..0d3e014 100644
> > --- a/drivers/gpu/drm/i915/intel_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > @@ -3316,8 +3316,10 @@ skl_compute_linetime_wm(struct drm_crtc *crtc, struct skl_pipe_wm_parameters *p)
> >         if (!to_intel_crtc(crtc)->active)
> >                 return 0;
> >
> > -       return DIV_ROUND_UP(8 * p->pipe_htotal * 1000, p->pixel_rate);
> > +       if (WARN_ON(p->pixel_rate == 0))
> > +               return 0;
> >
> > +       return DIV_ROUND_UP(8 * p->pipe_htotal * 1000, p->pixel_rate);
> >  }
> >
> >  static void skl_compute_transition_wm(struct drm_crtc *crtc,
> > --
> > 2.1.4
> >
> 
> 
> 
> -- 
> Paulo Zanoni
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch