linux-kernel - [PATCH 5.15 146/230] drm/mediatek: Detect CMDQ execution timeout

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20220711090608.203578148@linuxfoundation.org>
Date:   Mon, 11 Jul 2022 11:06:42 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Chun-Kuang Hu <chunkuang.hu@...nel.org>,
        "jason-jh.lin" <jason-jh.lin@...iatek.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.15 146/230] drm/mediatek: Detect CMDQ execution timeout

From: Chun-Kuang Hu <chunkuang.hu@...nel.org>

[ 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@...nel.org>
Signed-off-by: jason-jh.lin <jason-jh.lin@...iatek.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

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);
 }
 
-- 
2.35.1