This is a note to let you know that I've just added the patch titled drm/mediatek: hdmi: Perform NULL pointer check for mtk_hdmi_conf to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-mediatek-hdmi-perform-null-pointer-check-for-mtk.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit a7c7c0746b8a97d4903118ad6990fd04d4c58175 Author: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx> Date: Thu Oct 28 09:43:11 2021 +0200 drm/mediatek: hdmi: Perform NULL pointer check for mtk_hdmi_conf [ Upstream commit 3b8e19a0aa3933a785be9f1541afd8d398c4ec69 ] 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 <angelogioacchino.delregno@xxxxxxxxxxxxx> Signed-off-by: Chun-Kuang Hu <chunkuang.hu@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi.c b/drivers/gpu/drm/mediatek/mtk_hdmi.c index 5838c44cbf6f0..3196189429bcf 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;