6.6-stable review patch. If anyone has any objections, please let me know.
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From: Douglas Anderson dianders@chromium.org
[ Upstream commit 106a6de46cf4887d535018185ec528ce822d6d84 ]
The function mtk_dp_wait_hpd_asserted() may be called before the `mtk_dp->drm_dev` pointer is assigned in mtk_dp_bridge_attach(). Specifically it can be called via this callpath: - mtk_edp_wait_hpd_asserted - [panel probe] - dp_aux_ep_probe
Using "drm" level prints anywhere in this callpath causes a NULL pointer dereference. Change the error message directly in mtk_dp_wait_hpd_asserted() to dev_err() to avoid this. Also change the error messages in mtk_dp_parse_capabilities(), which is called by mtk_dp_wait_hpd_asserted().
While touching these prints, also add the error code to them to make future debugging easier.
Fixes: 7eacba9a083b ("drm/mediatek: dp: Add .wait_hpd_asserted() for AUX bus") Signed-off-by: Douglas Anderson dianders@chromium.org Reviewed-by: CK Hu ck.hu@mediatek.com Link: https://patchwork.kernel.org/project/dri-devel/patch/20250116094249.1.I29b0b... Signed-off-by: Chun-Kuang Hu chunkuang.hu@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/mediatek/mtk_dp.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c index be4de26c77f91..199527643093a 100644 --- a/drivers/gpu/drm/mediatek/mtk_dp.c +++ b/drivers/gpu/drm/mediatek/mtk_dp.c @@ -1648,7 +1648,7 @@ static int mtk_dp_parse_capabilities(struct mtk_dp *mtk_dp)
ret = drm_dp_dpcd_readb(&mtk_dp->aux, DP_MSTM_CAP, &val); if (ret < 1) { - drm_err(mtk_dp->drm_dev, "Read mstm cap failed\n"); + dev_err(mtk_dp->dev, "Read mstm cap failed: %zd\n", ret); return ret == 0 ? -EIO : ret; }
@@ -1658,7 +1658,7 @@ static int mtk_dp_parse_capabilities(struct mtk_dp *mtk_dp) DP_DEVICE_SERVICE_IRQ_VECTOR_ESI0, &val); if (ret < 1) { - drm_err(mtk_dp->drm_dev, "Read irq vector failed\n"); + dev_err(mtk_dp->dev, "Read irq vector failed: %zd\n", ret); return ret == 0 ? -EIO : ret; }
@@ -1941,7 +1941,7 @@ static int mtk_dp_wait_hpd_asserted(struct drm_dp_aux *mtk_aux, unsigned long wa
ret = mtk_dp_parse_capabilities(mtk_dp); if (ret) { - drm_err(mtk_dp->drm_dev, "Can't parse capabilities\n"); + dev_err(mtk_dp->dev, "Can't parse capabilities: %d\n", ret); return ret; }