drm/i915: Fix divide by zero on watermark update
authorMika Kuoppala <mika.kuoppala@linux.intel.com>
Thu, 16 Jul 2015 16:36:51 +0000 (19:36 +0300)
committerDaniel Vetter <daniel.vetter@ffwll.ch>
Fri, 17 Jul 2015 07:06:40 +0000 (09:06 +0200)
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)

Cc: Paulo Zanoni <przanoni@gmail.com>
Cc: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drivers/gpu/drm/i915/intel_pm.c

index 5eeddc9..0d3e014 100644 (file)
@@ -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,