The difference between drm_atomic_helper_commit_tail() and drm_atomic_helper_commit_tail_rpm() is drm_atomic_helper_commit_tail() will commit plane first and then enable crtc, drm_atomic_helper_commit_tail_rpm() will enable crtc first and then commit plane. Before mediatek-drm enables crtc, the power and clk required by OVL have not been turned on, so the commit plane cannot be committed before crtc is enabled. That means OVL layer should not be enabled before crtc is enabled. Therefore, the atomic_commit_tail of mediatek-drm is hooked with drm_atomic_helper_commit_tail_rpm(). Another reason is that the plane_state of drm_atomic_state is not synchronized with the plane_state stored in mtk_crtc during crtc enablng, so just set all planes to disabled. Fixes: 119f5173628a ("drm/mediatek: Add DRM Driver for Mediatek SoC MT8173.") Signed-off-by: Jason-JH.Lin <jason-jh.lin@xxxxxxxxxxxx> Reviewed-by: Alexandre Mergnat <amergnat@xxxxxxxxxxxx> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx> --- drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c index d40142842f85..51d10e65004e 100644 --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c @@ -410,6 +410,9 @@ static int mtk_crtc_ddp_hw_init(struct mtk_drm_crtc *mtk_crtc) unsigned int local_layer; plane_state = to_mtk_plane_state(plane->state); + + /* should not enable layer before crtc enabled */ + plane_state->pending.enable = false; comp = mtk_drm_ddp_comp_for_plane(crtc, plane, &local_layer); if (comp) mtk_ddp_comp_layer_config(comp, local_layer, -- 2.18.0