[Intel-gfx] [PATCH] drm/i915: Only disable visible planes in intel_crtc_disable_planes

[João Paulo Rechi Vita]

On 21 September 2015 at 09:05, Maarten Lankhorst
<maarten.lankhorst at linux.intel.com> wrote:
> This is fix for a regression introduced by 27321ae88c70104df
> "drm/i915: Use the disable callback for disabling planes."
>
> Disabling invisible planes may cause recalculation of
> watermarks, which is a problem because the software state
> is not yet in sync with the hardware state.
> This may result in a black screen during kernel boot and
> plymouth splash until any input action is performed in X.
>
> Explicitly checking for plane visibility fixes the regression.
> This is a patch for v4.2 only, v4.3 needs a different fix because
> it was fixed by d032ffa04cf7c6f
> "drm/i915: Handle disabling planes better, v2."
>
> but later broken again in
> 4cf0ebbd4fafbdf "drm/i915: Rework plane readout."
>
> This will be fixed in v4.3 by:
> "drm/i915: Add .get_hw_state() method for planes"
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91952
> Cc: João Paulo Rechi Vita <jprvita at endlessm.com>
> Cc: stable at vger.kernel.org # v4.2 only

Tested-by: João Paulo Rechi Vita <jprvita at endlessm.com>