[Intel-gfx] [PATCH] drm/i915/display: clear plane color control register when turn plane off

[Ville Syrjälä]

On Mon, Aug 01, 2022 at 11:16:16PM +0800, Lee Shawn C wrote:
> Customer report abnormal display output while switch eDP off sometimes.
> In current display disable flow, plane will be off at first. Then turn
> eDP off and disable HW pipe line. We found the abnormal pixel comes
> after turn plane off. Clear plane color ctl register when driver disable
> plane can solve this symptom.
> 
> Signed-off-by: Lee Shawn C <shawn.c.lee at intel.com>
> Reviewed-by: Uma Shankar <uma.shankar at intel.com>
> ---
>  drivers/gpu/drm/i915/display/skl_universal_plane.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/skl_universal_plane.c b/drivers/gpu/drm/i915/display/skl_universal_plane.c
> index caa03324a733..90977cfb7ebb 100644
> --- a/drivers/gpu/drm/i915/display/skl_universal_plane.c
> +++ b/drivers/gpu/drm/i915/display/skl_universal_plane.c
> @@ -620,6 +620,8 @@ skl_plane_disable_arm(struct intel_plane *plane,
>  
>  	intel_de_write_fw(dev_priv, PLANE_CTL(pipe, plane_id), 0);
>  	intel_de_write_fw(dev_priv, PLANE_SURF(pipe, plane_id), 0);
> +	if (DISPLAY_VER(dev_priv) >= 10)
> +		intel_de_write_fw(dev_priv, PLANE_COLOR_CTL(pipe, plane_id), 0);
>  }
>  
>  static void
> @@ -638,6 +640,7 @@ icl_plane_disable_arm(struct intel_plane *plane,
>  	intel_psr2_disable_plane_sel_fetch(plane, crtc_state);
>  	intel_de_write_fw(dev_priv, PLANE_CTL(pipe, plane_id), 0);
>  	intel_de_write_fw(dev_priv, PLANE_SURF(pipe, plane_id), 0);
> +	intel_de_write_fw(dev_priv, PLANE_COLOR_CTL(pipe, plane_id), 0);

This makes no sense. The register value shouldn't even get latched
since you wrote the arming register (PLANE_SURF) before this one.

What platform is the problematic machine?

>  }
>  
>  static bool
> -- 
> 2.17.1

-- 
Ville Syrjälä
Intel