[PATCH 4/6] amd/display: add cursor check for YUV underlying pipe

[Simon Ser]

The cursor plane can't be displayed if the underlying pipe isn't
using an RGB format. Reject such atomic commits so that user-space
can have a fallback instead of an invisible cursor.

In theory we could support YUV if the cursor is also YUV, but at the
moment only ARGB8888 cursors are supported.

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 | 7 +++++++
 1 file changed, 7 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 a5d6010405bf..6e7f4a182e89 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -9250,6 +9250,13 @@ static int dm_check_crtc_cursor(struct drm_atomic_state *state,
 		return -EINVAL;
 	}
 
+	/* In theory we could probably support YUV cursors when the underlying
+	 * plane uses a YUV format, but there's no use-case for it yet. */
+	if (new_underlying_state->fb->format->is_yuv) {
+		drm_dbg_atomic(crtc->dev, "Cursor plane can't be used with YUV underlying plane\n");
+		return -EINVAL;
+	}
+
 	return 0;
 }
 
-- 
2.30.1