[PATCH] drm/amd/display: check fb of primary plane

[Sefa Eyeoglu]

Sometimes the primary plane might not be initialized (yet), which
causes dm_check_crtc_cursor to divide by zero.
Apparently a weird state before a S3-suspend causes the aforementioned
divide-by-zero error when resuming from S3.  This was explained in
bug 212293 on Bugzilla.

To avoid this divide-by-zero error we check if the primary plane's fb
isn't NULL.  If it's NULL the src_w and src_h attributes will be 0,
which would cause a divide-by-zero.

This fixes Bugzilla report 212293
https://bugzilla.kernel.org/show_bug.cgi?id=212293

Fixes: 12f4849a1cfd69f3 ("drm/amd/display: check cursor scaling")
Signed-off-by: Sefa Eyeoglu <contact at scrumplex.net>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

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 573cf17262da4e11..fbb1ac223ccbb62a 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -9267,7 +9267,8 @@ static int dm_check_crtc_cursor(struct drm_atomic_state *state,
 
 	new_cursor_state = drm_atomic_get_new_plane_state(state, crtc->cursor);
 	new_primary_state = drm_atomic_get_new_plane_state(state, crtc->primary);
-	if (!new_cursor_state || !new_primary_state || !new_cursor_state->fb) {
+	if (!new_cursor_state || !new_primary_state ||
+		!new_cursor_state->fb || !new_primary_state->fb) {
 		return 0;
 	}
 
-- 
2.31.0