Re: [PATCH] drm/i915/GLK: Properly handle plane CSC for BT2020 framebuffers

Ville Syrjälä
2019-05-02T10:15:08Z

On Thu, May 02, 2019 at 03:19:42PM +0530, Shashank Sharma wrote:
> Framebuffer formats P01x are supported by GLK, but the function which
> handles CSC on plane color control register, still expectes the input
> buffer to be REC709. This can cause inaccurate output for direct P01x
> flips.
>
> This patch checks if the color_encoding property is set to YCBCR_2020,
> and enables the corresponding color conversion mode on plane CSC.
>
> PS: renamed variable plane_color_ctl to color_ctl for 80 char stuff.
>
> Cc: Ville Syrjala <ville.syrjala@intel.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@intel.com>
> Cc: Uma Shankar <uma.shankar@intel.com>
> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
> ---
> drivers/gpu/drm/i915/intel_display.c | 26 ++++++++++++++++----------
> 1 file changed, 16 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index dd65d7c521c1..2d4d3128bf1f 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -3868,24 +3868,30 @@ u32 glk_plane_color_ctl(const struct intel_crtc_state *crtc_state,
> to_i915(plane_state->base.plane->dev);
> const struct drm_framebuffer *fb = plane_state->base.fb;
> struct intel_plane *plane = to_intel_plane(plane_state->base.plane);
> - u32 plane_color_ctl = 0;
> + u32 color_ctl = 0;
>
> - plane_color_ctl |= PLANE_COLOR_PLANE_GAMMA_DISABLE;
> - plane_color_ctl |= glk_plane_color_ctl_alpha(plane_state);
> + color_ctl |= PLANE_COLOR_PLANE_GAMMA_DISABLE;
> + color_ctl |= glk_plane_color_ctl_alpha(plane_state);
>
> if (fb->format->is_yuv && !icl_is_hdr_plane(dev_priv, plane->id)) {
> - if (plane_state->base.color_encoding == DRM_COLOR_YCBCR_BT709)
> - plane_color_ctl |= PLANE_COLOR_CSC_MODE_YUV709_TO_RGB709;
> - else
> - plane_color_ctl |= PLANE_COLOR_CSC_MODE_YUV601_TO_RGB709;
> + switch (plane_state->base.color_encoding) {
> + case DRM_COLOR_YCBCR_BT709:
> + color_ctl |= PLANE_COLOR_CSC_MODE_YUV709_TO_RGB709;
> + break;
> + case DRM_COLOR_YCBCR_BT2020:
> + color_ctl |= PLANE_COLOR_CSC_MODE_YUV2020_TO_RGB2020;
> + break;
> + default:
> + color_ctl |= PLANE_COLOR_CSC_MODE_YUV601_TO_RGB709;
> + }

This isn't going to do anything without adjusting the property supported
encodings as well.

>
> if (plane_state->base.color_range == DRM_COLOR_YCBCR_FULL_RANGE)
> - plane_color_ctl |= PLANE_COLOR_YUV_RANGE_CORRECTION_DISABLE;
> + color_ctl |= PLANE_COLOR_YUV_RANGE_CORRECTION_DISABLE;
> } else if (fb->format->is_yuv) {
> - plane_color_ctl |= PLANE_COLOR_INPUT_CSC_ENABLE;
> + color_ctl |= PLANE_COLOR_INPUT_CSC_ENABLE;
> }
>
> - return plane_color_ctl;
> + return color_ctl;
> }
>
> static int
> --
> 2.17.1
>
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--
Ville Syrjälä
Intel