In commit 41ca9caaae0b ("drm/mediatek: hdmi: Add check for CEA modes only")
a check for CEA modes was added to function mtk_hdmi_bridge_mode_valid()
in order to address possible issues on MT8167; moreover, with commit
c91026a938c2 ("drm/mediatek: hdmi: Add optional limit on maximal HDMI mode 
clock")
another similar check was introduced.

Unfortunately though, at the time of writing, MT8173 does not provide
any mtk_hdmi_conf structure and this is crashing the kernel with NULL
pointer upon entering mtk_hdmi_bridge_mode_valid(), which happens as
soon as a HDMI cable gets plugged in.

To fix this regression, add a NULL pointer check for hdmi->conf in the
said function, restoring HDMI functionality and avoiding NULL pointer
kernel panics.

Fixes: 41ca9caaae0b ("drm/mediatek: hdmi: Add check for CEA modes only")
Fixes: c91026a938c2 ("drm/mediatek: hdmi: Add optional limit on maximal HDMI 
mode clock")
Signed-off-by: AngeloGioacchino Del Regno 
<[email protected]>
---
 drivers/gpu/drm/mediatek/mtk_hdmi.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi.c 
b/drivers/gpu/drm/mediatek/mtk_hdmi.c
index 5838c44cbf6f..3196189429bc 100644
--- a/drivers/gpu/drm/mediatek/mtk_hdmi.c
+++ b/drivers/gpu/drm/mediatek/mtk_hdmi.c
@@ -1224,12 +1224,14 @@ static int mtk_hdmi_bridge_mode_valid(struct drm_bridge 
*bridge,
                        return MODE_BAD;
        }
 
-       if (hdmi->conf->cea_modes_only && !drm_match_cea_mode(mode))
-               return MODE_BAD;
+       if (hdmi->conf) {
+               if (hdmi->conf->cea_modes_only && !drm_match_cea_mode(mode))
+                       return MODE_BAD;
 
-       if (hdmi->conf->max_mode_clock &&
-           mode->clock > hdmi->conf->max_mode_clock)
-               return MODE_CLOCK_HIGH;
+               if (hdmi->conf->max_mode_clock &&
+                   mode->clock > hdmi->conf->max_mode_clock)
+                       return MODE_CLOCK_HIGH;
+       }
 
        if (mode->clock < 27000)
                return MODE_CLOCK_LOW;
-- 
2.33.0

Reply via email to