On 1/21/22 14:24, Alexander Stein wrote:
Am Freitag, 21. Januar 2022, 14:14:01 CET schrieb Marek Vasut:
On 1/21/22 14:12, Alexander Stein wrote:
Do not deference the NULL pointer if the bridge does not return a
bridge state. 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.stein@xxxxxxxxxxxxxxx>
---
This can happen if a "ti,sn75lvds83", "lvds-encoder" bridge is attached
to it. atomic_get_input_bus_fmts is only implemented for the
lvds-decoder case.
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"
Shouldn't this be fixed on the bridge driver side instead ?
Which bridge driver do you use ?
It's drivers/gpu/drm/bridge/lvds-codec.c. I thought naming the compatibles
would suffice. I consider a patch for the bridge driver as a separate issue,
hence the warning from mxsfb. Although I'm unsure how/what to implement.
Similar to the encode case where the bus format is specified in DT?
I'm sorry, I missed the lvds-codec part. Laurent is already on CC.
Anyway, mxsfb should not never dereference the NULL pointer which
drm_atomic_get_new_bridge_state is allowed to return.
That line ^ should be in the commit message.
