[PATCH v2 4/5] amd/display: add cursor alpha and blend mode checks

[Simon Ser]

We don't want a semi-transparent overlay to make the cursor plane
semi-transparent as well. Same for the pixel blend mode.

Signed-off-by: Simon Ser <contact at emersion.fr>
Cc: Alex Deucher <alexander.deucher at amd.com>
Cc: Harry Wentland <hwentlan at amd.com>
Cc: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 98df550c3979..b4f6e2985b8a 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -9501,6 +9501,16 @@ static int dm_check_crtc_cursor(struct drm_atomic_state *state,
 		return -EINVAL;
 	}
 
+	if (new_underlying_state->alpha != DRM_BLEND_ALPHA_OPAQUE) {
+		drm_dbg_atomic(crtc->dev, "Cursor plane can't be used with non-opaque underlying plane\n");
+		return -EINVAL;
+	}
+
+	if (new_underlying_state->pixel_blend_mode != DRM_MODE_BLEND_PREMULTI) {
+		drm_dbg_atomic(crtc->dev, "Cursor plane can't be used with non-premultiplied underlying plane\n");
+		return -EINVAL;
+	}
+
 	return 0;
 }
 
-- 
2.30.2