[PATCH v4.1 1/3] drm/i915: Force background color to black for gen9+ (v2)

[Ville Syrjälä]

On Wed, Jan 30, 2019 at 10:51:20AM -0800, Matt Roper wrote:
> We don't yet allow userspace to control the CRTC background color, but
> we should manually program the color to black to ensure the BIOS didn't
> leave us with some other color.  We should also set the pipe gamma and
> pipe CSC bits so that the background color goes through the same color
> management transformations that a plane with black pixels would.
> 
> v2: Rename register to SKL_BOTTOM_COLOR to more closely follow
>     bspec naming.  (Ville)
> 
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Signed-off-by: Matt Roper <matthew.d.roper at intel.com>

Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

> ---
>  drivers/gpu/drm/i915/i915_reg.h      |  6 ++++++
>  drivers/gpu/drm/i915/intel_display.c | 19 +++++++++++++++++++
>  2 files changed, 25 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 03adcf3838de..a64deeb4e517 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -5710,6 +5710,12 @@ enum {
>  #define   PIPEMISC_DITHER_TYPE_SP	(0 << 2)
>  #define PIPEMISC(pipe)			_MMIO_PIPE2(pipe, _PIPE_MISC_A)
>  
> +/* Skylake+ pipe bottom (background) color */
> +#define _SKL_BOTTOM_COLOR_A		0x70034
> +#define   SKL_BOTTOM_COLOR_GAMMA_ENABLE	(1 << 31)
> +#define   SKL_BOTTOM_COLOR_CSC_ENABLE	(1 << 30)
> +#define SKL_BOTTOM_COLOR(pipe)		_MMIO_PIPE2(pipe, _SKL_BOTTOM_COLOR_A)
> +
>  #define VLV_DPFLIPSTAT				_MMIO(VLV_DISPLAY_BASE + 0x70028)
>  #define   PIPEB_LINE_COMPARE_INT_EN		(1 << 29)
>  #define   PIPEB_HLINE_INT_EN			(1 << 28)
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 539d8915b55f..a025efb1d7c6 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -3930,6 +3930,16 @@ static void intel_update_pipe_config(const struct intel_crtc_state *old_crtc_sta
>  		else if (old_crtc_state->pch_pfit.enabled)
>  			ironlake_pfit_disable(old_crtc_state);
>  	}
> +
> +	/*
> +	 * We don't (yet) allow userspace to control the pipe background color,
> +	 * so force it to black, but apply pipe gamma and CSC so that its
> +	 * handling will match how we program our planes.
> +	 */
> +	if (INTEL_GEN(dev_priv) >= 9)
> +		I915_WRITE(SKL_BOTTOM_COLOR(crtc->pipe),
> +			   SKL_BOTTOM_COLOR_GAMMA_ENABLE |
> +			   SKL_BOTTOM_COLOR_CSC_ENABLE);
>  }
>  
>  static void intel_fdi_normal_train(struct intel_crtc *crtc)
> @@ -15488,6 +15498,15 @@ static void intel_sanitize_crtc(struct intel_crtc *crtc,
>  			    plane->base.type != DRM_PLANE_TYPE_PRIMARY)
>  				intel_plane_disable_noatomic(crtc, plane);
>  		}
> +
> +		/*
> +		 * Disable any background color set by the BIOS, but enable the
> +		 * gamma and CSC to match how we program our planes.
> +		 */
> +		if (INTEL_GEN(dev_priv) >= 9)
> +			I915_WRITE(SKL_BOTTOM_COLOR(crtc->pipe),
> +				   SKL_BOTTOM_COLOR_GAMMA_ENABLE |
> +				   SKL_BOTTOM_COLOR_CSC_ENABLE);
>  	}
>  
>  	/* Adjust the state of the output pipe according to whether we
> -- 
> 2.14.5

-- 
Ville Syrjälä
Intel