[Intel-gfx] [PATCH] drm/i915: Ignore panel type from OpRegion on SKL

[James Bottomley]

On Tue, 2016-07-12 at 15:00 +0300, ville.syrjala at linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Dell XPS 13 9350 apparently doesn't like it when we use the panel
> type
> from OpRegion. The OpRegion panel type (0) tells us to use use low
> vswing for eDP, whereas the VBT panel type (2) tells us to use normal
> vswing. The problem is that low vswing results in some display
> flickers.
> Since no one seems to know how this stuff is supposed to be handled,
> let's just ignore the OpRegion panel type on SKL for now.
> 
> Reported-by: James Bottomley <James.Bottomley at HansenPartnership.com>
> Cc: James Bottomley <James.Bottomley at HansenPartnership.com>
> Cc: drm-intel-fixes at lists.freedesktop.org
> References: https://lists.freedesktop.org/archives/intel-gfx/2016-Jun
> e/098826.html
> Fixes: a05628195a0d ("drm/i915: Get panel_type from OpRegion panel
> details")
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

This one doesn't actually compile on git head:


drivers/gpu/drm/i915/intel_opregion.c: In function
‘intel_opregion_get_panel_type’:
drivers/gpu/drm/i915/intel_opregion.c:1047:17: error: ‘dev_priv’
undeclared (first use in this function)
  if (IS_SKYLAKE(dev_priv))

So it's going to be hard to backport to stable.

However, I've applied it on top of the drm branch and there have been
no flicker problems after 12h of use, so you can add a tested by from
me if you want.

James