From a9ef192c48844831d45654dfec89c35af8b3fa32 Mon Sep 17 00:00:00 2001 From: Wojciech Macek Date: Wed, 17 Apr 2024 10:38:19 +0000 Subject: [PATCH] drm/mediatek: dp: Fix mtk_dp_aux_transfer return value [ Upstream commit 8431fff9e0f3fc1c5844cf99a73b49b63ceed481 ] In case there is no DP device attached to the port the transfer function should return IO error, similar to what other drivers do. In case EAGAIN is returned then any read from /dev/drm_dp_aux device ends up in an infinite loop as the upper layers constantly repeats the transfer request. Fixes: f70ac097a2cf ("drm/mediatek: Add MT8195 Embedded DisplayPort driver") Signed-off-by: Wojciech Macek Reviewed-by: AngeloGioacchino Del Regno Reviewed-by: CK Hu Link: https://patchwork.kernel.org/project/dri-devel/patch/20240417103819.990512-1-wmacek@chromium.org/ Signed-off-by: Chun-Kuang Hu Signed-off-by: Sasha Levin --- drivers/gpu/drm/mediatek/mtk_dp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c index 4bea46ae4dbf..c24eeb7ffde7 100644 --- a/drivers/gpu/drm/mediatek/mtk_dp.c +++ b/drivers/gpu/drm/mediatek/mtk_dp.c @@ -2058,7 +2058,7 @@ static ssize_t mtk_dp_aux_transfer(struct drm_dp_aux *mtk_aux, if (mtk_dp->bridge.type != DRM_MODE_CONNECTOR_eDP && !mtk_dp->train_info.cable_plugged_in) { - ret = -EAGAIN; + ret = -EIO; goto err; }