[PATCH v2 2/2] drm: mxsfb: Fix NULL pointer dereference

[Alexander Stein]

mxsfb should not never dereference the NULL pointer which
drm_atomic_get_new_bridge_state is allowed to return.
Assume a fixed format instead.

Fixes: commit b776b0f00f24 ("drm: mxsfb: Use bus_format from the nearest bridge 
if present")
Signed-off-by: Alexander Stein <alexander.st...@ew.tq-group.com>
---
 drivers/gpu/drm/mxsfb/mxsfb_kms.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c 
b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
index 0655582ae8ed..4cfb6c001679 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
@@ -361,7 +361,11 @@ static void mxsfb_crtc_atomic_enable(struct drm_crtc *crtc,
                bridge_state =
                        drm_atomic_get_new_bridge_state(state,
                                                        mxsfb->bridge);
-               bus_format = bridge_state->input_bus_cfg.format;
+               if (!bridge_state)
+                       bus_format = MEDIA_BUS_FMT_FIXED;
+               else
+                       bus_format = bridge_state->input_bus_cfg.format;
+
                if (bus_format == MEDIA_BUS_FMT_FIXED) {
                        dev_warn_once(drm->dev,
                                      "Bridge does not provide bus format, 
assuming MEDIA_BUS_FMT_RGB888_1X24.\n"
-- 
2.25.1