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Check the return value to confirm that AUX communication is successful. Fixes: d9e6ea02fc3f ("drm/mediatek: dp: Add MT8195 External DisplayPort support") Signed-off-by: Liankun Yang --- Changes in V2: - Modify Fixes in Commit Message. Per suggestion from the previous thread: https://patchwork.kernel.org/project/linux-mediatek/patch/20240930092000.5385-1-liankun.yang@mediatek.com/ --- drivers/gpu/drm/mediatek/mtk_dp.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c index 1cc916b16471..9dc68ec2ff43 100644 --- a/drivers/gpu/drm/mediatek/mtk_dp.c +++ b/drivers/gpu/drm/mediatek/mtk_dp.c @@ -2101,6 +2101,7 @@ static enum drm_connector_status mtk_dp_bdg_detect(struct drm_bridge *bridge) enum drm_connector_status ret = connector_status_disconnected; bool enabled = mtk_dp->enabled; u8 sink_count = 0; + size_t value; if (!mtk_dp->train_info.cable_plugged_in) return ret; @@ -2115,7 +2116,12 @@ static enum drm_connector_status mtk_dp_bdg_detect(struct drm_bridge *bridge) * function, we just need to check the HPD connection to check * whether we connect to a sink device. */ - drm_dp_dpcd_readb(&mtk_dp->aux, DP_SINK_COUNT, &sink_count); + value = drm_dp_dpcd_readb(&mtk_dp->aux, DP_SINK_COUNT, &sink_count); + if (value < 0) { + drm_err(mtk_dp->drm_dev, "Failed to read DP Sink Count: %zd\n", value); + return ret; + } + if (DP_GET_SINK_COUNT(sink_count)) ret = connector_status_connected; -- 2.45.2