[RFC 1/1] SWDEV476969 - dm: Fail dm_atomic_check if cursor overlay is required at MAX_SURFACES

[Zaeem Mohamed]

[why]
Prevent index-out-of-bounds due to requiring cursor overlay when
plane_count is MAX_SURFACES.

[how]
Bounds check on plane_count when requiring overlay cursor.

Co-developed-by: Melissa Wen <mwen at igalia.com>
Signed-off-by: Zaeem Mohamed <zaeem.mohamed at amd.com>
---
 amdgpu_dm/amdgpu_dm.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/amdgpu_dm/amdgpu_dm.c b/amdgpu_dm/amdgpu_dm.c
index df83e7b42b..c2595efb74 100644
--- a/amdgpu_dm/amdgpu_dm.c
+++ b/amdgpu_dm/amdgpu_dm.c
@@ -11676,6 +11676,12 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
 		 * need to be added for DC to not disable a plane by mistake
 		 */
 		if (dm_new_crtc_state->cursor_mode == DM_CURSOR_OVERLAY_MODE) {
+			if(dc->current_state->stream_status->plane_count >= MAX_SURFACES){
+				drm_dbg_driver(crtc->dev,
+				       "Can't enable cursor plane with %d planes\n", MAX_SURFACES);
+				ret = -EINVAL;
+				goto fail;
+			}
 			ret = drm_atomic_add_affected_planes(state, crtc);
 			if (ret)
 				goto fail;
@@ -11769,8 +11775,16 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
 
 		/* Overlay cusor not subject to native cursor restrictions */
 		dm_new_crtc_state = to_dm_crtc_state(new_crtc_state);
-		if (dm_new_crtc_state->cursor_mode == DM_CURSOR_OVERLAY_MODE)
+		if (dm_new_crtc_state->cursor_mode == DM_CURSOR_OVERLAY_MODE){
+			if(dc->current_state->stream_status->plane_count > MAX_SURFACES){
+				drm_dbg_driver(crtc->dev,
+				       "Can't enable cursor plane with %d planes\n", MAX_SURFACES);
+				ret = -EINVAL;
+				goto fail;
+			}
+			
 			continue;
+		}
 
 		/* Check if rotation or scaling is enabled on DCN401 */
 		if ((drm_plane_mask(crtc->cursor) & new_crtc_state->plane_mask) &&
-- 
2.34.1