drm/i915: Try to suppress more spurious PCH underruns on ILK-IVB
authorVille Syrjälä <ville.syrjala@linux.intel.com>
Thu, 24 May 2018 19:04:05 +0000 (22:04 +0300)
committerVille Syrjälä <ville.syrjala@linux.intel.com>
Fri, 25 May 2018 15:00:26 +0000 (18:00 +0300)
commitea80a661fe56f27821a4fc40f8149be650ec913d
tree74b04c58e9775381e908107945ef6539eb9dca0f
parent10ed55e4d94c39cf32058cc0a2a7935b67e4bc9c
drm/i915: Try to suppress more spurious PCH underruns on ILK-IVB

My ILK seems to generate a spurious PCH underrun with most interlaced
HDMI modes. Add a second vblank wait to avoid it.

We have seen some spurious PCH underruns still in CI as well, some
of which seem to be progressive DP. The logs also point towards some
spurious underrins with progressive HDMI on SNB. While I don't have
a solid explanation for those let's try to kill all the birds with one
stone and always do the double wait.

Buzilla: https://bugs.freedesktop.org/show_bug.cgi?id=106387
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180524190406.2973-1-ville.syrjala@linux.intel.com
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
drivers/gpu/drm/i915/intel_display.c