[Intel-gfx] [PATCH v2] drm/i915/GLK: Properly handle plane CSC for BT2020 framebuffers

[Shashank Sharma]

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.

V2: Expose the YCBCR_BT2020 value in enum values of supported encoding
    formats.

Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst at intel.com>
Cc: Uma Shankar <uma.shankar at intel.com>
Signed-off-by: Shashank Sharma <shashank.sharma at intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 26 ++++++++++++++++----------
 drivers/gpu/drm/i915/intel_sprite.c  | 10 ++++++++--
 2 files changed, 24 insertions(+), 12 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;
+		}
 
 		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
diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
index 2913e89280d7..f1024c2f47cb 100644
--- a/drivers/gpu/drm/i915/intel_sprite.c
+++ b/drivers/gpu/drm/i915/intel_sprite.c
@@ -2238,6 +2238,7 @@ skl_universal_plane_create(struct drm_i915_private *dev_priv,
 	struct intel_plane *plane;
 	enum drm_plane_type plane_type;
 	unsigned int supported_rotations;
+	unsigned int supported_encodings;
 	unsigned int possible_crtcs;
 	const u64 *modifiers;
 	const u32 *formats;
@@ -2325,9 +2326,14 @@ skl_universal_plane_create(struct drm_i915_private *dev_priv,
 					   DRM_MODE_ROTATE_0,
 					   supported_rotations);
 
+	supported_encodings = BIT(DRM_COLOR_YCBCR_BT601) |
+			      BIT(DRM_COLOR_YCBCR_BT709);
+
+	if (INTEL_GEN(dev_priv) >= 10 || IS_GEMINILAKE(dev_priv))
+		supported_encodings |= DRM_COLOR_YCBCR_BT2020;
+
 	drm_plane_create_color_properties(&plane->base,
-					  BIT(DRM_COLOR_YCBCR_BT601) |
-					  BIT(DRM_COLOR_YCBCR_BT709),
+					  supported_encodings,
 					  BIT(DRM_COLOR_YCBCR_LIMITED_RANGE) |
 					  BIT(DRM_COLOR_YCBCR_FULL_RANGE),
 					  DRM_COLOR_YCBCR_BT709,
-- 
2.17.1