This is a note to let you know that I've just added the patch titled drm/mediatek: Detect CMDQ execution timeout 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-detect-cmdq-execution-timeout.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 e00118f8bbf5550fc398d49351084f1d9cd2726b Author: Chun-Kuang Hu <chunkuang.hu@xxxxxxxxxx> Date: Wed Oct 27 10:18:54 2021 +0800 drm/mediatek: Detect CMDQ execution timeout [ Upstream commit eaf80126aba6fd1754837eec91e4c8bbd58ae52e ] CMDQ is used to update display register in vblank period, so it should be execute in next 2 vblank. One vblank interrupt before send message (occasionally) and one vblank interrupt after cmdq done. If it fail to execute in next 3 vblank, tiemout happen. Signed-off-by: Chun-Kuang Hu <chunkuang.hu@xxxxxxxxxx> Signed-off-by: jason-jh.lin <jason-jh.lin@xxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c index e23e3224ac67..dad1f85ee315 100644 --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c @@ -54,6 +54,7 @@ struct mtk_drm_crtc { #if IS_REACHABLE(CONFIG_MTK_CMDQ) struct cmdq_client cmdq_client; u32 cmdq_event; + u32 cmdq_vblank_cnt; #endif struct device *mmsys_dev; @@ -227,7 +228,10 @@ struct mtk_ddp_comp *mtk_drm_ddp_comp_for_plane(struct drm_crtc *crtc, static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg) { struct cmdq_cb_data *data = mssg; + struct cmdq_client *cmdq_cl = container_of(cl, struct cmdq_client, client); + struct mtk_drm_crtc *mtk_crtc = container_of(cmdq_cl, struct mtk_drm_crtc, cmdq_client); + mtk_crtc->cmdq_vblank_cnt = 0; cmdq_pkt_destroy(data->pkt); } #endif @@ -483,6 +487,15 @@ static void mtk_drm_crtc_update_config(struct mtk_drm_crtc *mtk_crtc, cmdq_handle->pa_base, cmdq_handle->cmd_buf_size, DMA_TO_DEVICE); + /* + * CMDQ command should execute in next 3 vblank. + * One vblank interrupt before send message (occasionally) + * and one vblank interrupt after cmdq done, + * so it's timeout after 3 vblank interrupt. + * If it fail to execute in next 3 vblank, timeout happen. + */ + mtk_crtc->cmdq_vblank_cnt = 3; + mbox_send_message(mtk_crtc->cmdq_client.chan, cmdq_handle); mbox_client_txdone(mtk_crtc->cmdq_client.chan, 0); } @@ -499,11 +512,14 @@ static void mtk_crtc_ddp_irq(void *data) #if IS_REACHABLE(CONFIG_MTK_CMDQ) if (!priv->data->shadow_register && !mtk_crtc->cmdq_client.chan) + mtk_crtc_ddp_config(crtc, NULL); + else if (mtk_crtc->cmdq_vblank_cnt > 0 && --mtk_crtc->cmdq_vblank_cnt == 0) + DRM_ERROR("mtk_crtc %d CMDQ execute command timeout!\n", + drm_crtc_index(&mtk_crtc->base)); #else if (!priv->data->shadow_register) -#endif mtk_crtc_ddp_config(crtc, NULL); - +#endif mtk_drm_finish_page_flip(mtk_crtc); }