drm/i915: Avoid programming color HW blocks for NV12 Y planes

link_nv12_planes() currently copies the full UV plane hw state to
the Y plane. This includes the color pipeline blobs (ctm, degamma_lut,
gamma_lut, lut_3d) which is incorrect as we don't need to program these
HW blocks for Y plane.

This is harmless currently as the color pipeline uapi does not support
YUV (both packed and planar) formats but that can change in the future.

Add a new static helper intel_plane_y_copy_hw_state() that copies only
the rendering parameters a Y plane actually needs, leaving all color
pipeline blobs unset. Remove the helper intel_plane_copy_hw_state() as
there are no users for it.

v2:
- drop the extra spaces before ='s (Jani)

Cc: Jani Nikula <jani.nikula@intel.com>
Assisted-by: GitHub-Copilot:Claude-Sonnet-4.6
Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Link: https://patch.msgid.link/20260601082953.128539-3-chaitanya.kumar.borah@intel.com

2 files changed, 14 insertions, 10 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_plane.c b/drivers/gpu/drm/i915/display/intel_plane.c
index 74100629bb3e..5ae178e8a96b 100644
--- a/drivers/gpu/drm/i915/display/intel_plane.c
+++ b/drivers/gpu/drm/i915/display/intel_plane.c
@@ -450,16 +450,22 @@ void intel_plane_copy_uapi_to_hw_state(struct intel_atomic_state *state,
 	intel_plane_color_copy_uapi_to_hw_state(state, plane_state, from_plane_state, crtc);
 }
 
-void intel_plane_copy_hw_state(struct intel_plane_state *plane_state,
-			       const struct intel_plane_state *from_plane_state)
+static void intel_plane_y_copy_hw_state(struct intel_plane_state *y_plane_state,
+					const struct intel_plane_state *uv_plane_state)
 {
-	intel_plane_clear_hw_state(plane_state);
+	intel_plane_clear_hw_state(y_plane_state);
 
-	memcpy(&plane_state->hw, &from_plane_state->hw,
-	       sizeof(plane_state->hw));
+	y_plane_state->hw.crtc = uv_plane_state->hw.crtc;
+	y_plane_state->hw.fb = uv_plane_state->hw.fb;
+	if (y_plane_state->hw.fb)
+		drm_framebuffer_get(y_plane_state->hw.fb);
 
-	if (plane_state->hw.fb)
-		drm_framebuffer_get(plane_state->hw.fb);
+	y_plane_state->hw.alpha	= uv_plane_state->hw.alpha;
+	y_plane_state->hw.pixel_blend_mode = uv_plane_state->hw.pixel_blend_mode;
+	y_plane_state->hw.rotation = uv_plane_state->hw.rotation;
+	y_plane_state->hw.color_encoding = uv_plane_state->hw.color_encoding;
+	y_plane_state->hw.color_range = uv_plane_state->hw.color_range;
+	y_plane_state->hw.scaling_filter = uv_plane_state->hw.scaling_filter;
 }
 
 static void unlink_nv12_plane(struct intel_crtc_state *crtc_state,
@@ -1665,7 +1671,7 @@ static void link_nv12_planes(struct intel_crtc_state *crtc_state,
 	crtc_state->rel_data_rate[y_plane->id] = crtc_state->rel_data_rate_y[uv_plane->id];
 
 	/* Copy parameters to Y plane */
-	intel_plane_copy_hw_state(y_plane_state, uv_plane_state);
+	intel_plane_y_copy_hw_state(y_plane_state, uv_plane_state);
 	y_plane_state->uapi.src = uv_plane_state->uapi.src;
 	y_plane_state->uapi.dst = uv_plane_state->uapi.dst;
 
diff --git a/drivers/gpu/drm/i915/display/intel_plane.h b/drivers/gpu/drm/i915/display/intel_plane.h
index 87c79a644052..31a6229aea73 100644
--- a/drivers/gpu/drm/i915/display/intel_plane.h
+++ b/drivers/gpu/drm/i915/display/intel_plane.h
@@ -39,8 +39,6 @@ void intel_plane_copy_uapi_to_hw_state(struct intel_atomic_state *state,
 				       struct intel_plane_state *plane_state,
 				       const struct intel_plane_state *from_plane_state,
 				       struct intel_crtc *crtc);
-void intel_plane_copy_hw_state(struct intel_plane_state *plane_state,
-			       const struct intel_plane_state *from_plane_state);
 void intel_plane_async_flip(struct intel_dsb *dsb,
 			    struct intel_plane *plane,
 			    const struct intel_crtc_state *crtc_state,