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

[Jani Nikula]

On Mon, 21 Sep 2015, 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"

Stable will need that described as

commit <commit-id> upstream.

as the first line of the commit message.

BR,
Jani.

>
> 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
> ---
>  drivers/gpu/drm/i915/intel_display.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 87476ff181dd..a5f97cfd86d8 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -4863,7 +4863,8 @@ static void intel_crtc_disable_planes(struct drm_crtc *crtc)
>  
>  	intel_crtc_dpms_overlay_disable(intel_crtc);
>  	for_each_intel_plane(dev, intel_plane) {
> -		if (intel_plane->pipe == pipe) {
> +		if (intel_plane->pipe == pipe &&
> +		    to_intel_plane_state(intel_plane->base.state)->visible) {
>  			struct drm_crtc *from = intel_plane->base.crtc;
>  
>  			intel_plane->disable_plane(&intel_plane->base,
> -- 
> 2.1.0
>
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-- 
Jani Nikula, Intel Open Source Technology Center