linux-kernel - [PATCH] drm/mediatek: Fix config_updating flag never false when no mbox channel

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Message-ID: <20250224051301.3538484-1-jason-jh.lin@mediatek.com>
Date: Mon, 24 Feb 2025 13:12:21 +0800
From: Jason-JH Lin <jason-jh.lin@...iatek.com>
To: Chun-Kuang Hu <chunkuang.hu@...nel.org>, AngeloGioacchino Del Regno
	<angelogioacchino.delregno@...labora.com>
CC: "Jason-JH . Lin" <jason-jh.lin@...iatek.com>, Nancy Lin
	<nancy.lin@...iatek.com>, Singo Chang <singo.chang@...iatek.com>, Yongqiang
 Niu <yongqiang.niu@...iatek.com>, Sirius Wang <sirius.wang@...iatek.com>,
	Xavier Chang <xavier.chang@...iatek.com>, Fei Shao <fshao@...omium.org>,
	Chen-yu Tsai <wenst@...omium.org>, Pin-yen Lin <treapking@...omium.org>,
	<dri-devel@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>,
	<linux-mediatek@...ts.infradead.org>, <linux-arm-kernel@...ts.infradead.org>,
	<Project_Global_Chrome_Upstream_Group@...iatek.com>
Subject: [PATCH] drm/mediatek: Fix config_updating flag never false when no mbox channel

When CONFIG_MTK_CMDQ is enabled, if the display is controlled by the CPU
while other hardware is controlled by the GCE, the display will encounter
a mbox request channel failure.
However, it will still enter the CONFIG_MTK_CMDQ statement, causing the
config_updating flag to never be set to false. As a result, no page flip
event is sent back to user space, and the screen does not update.

Fixes: da03801ad08f ("drm/mediatek: Move mtk_crtc_finish_page_flip() to ddp_cmdq_cb()")
Signed-off-by: Jason-JH Lin <jason-jh.lin@...iatek.com>
---
 drivers/gpu/drm/mediatek/mtk_crtc.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_crtc.c b/drivers/gpu/drm/mediatek/mtk_crtc.c
index 5674f5707cca..cfc4867296b8 100644
--- a/drivers/gpu/drm/mediatek/mtk_crtc.c
+++ b/drivers/gpu/drm/mediatek/mtk_crtc.c
@@ -620,13 +620,14 @@ static void mtk_crtc_update_config(struct mtk_crtc *mtk_crtc, bool needs_vblank)
 
 		mbox_send_message(mtk_crtc->cmdq_client.chan, cmdq_handle);
 		mbox_client_txdone(mtk_crtc->cmdq_client.chan, 0);
+		goto update_config_out;
 	}
-#else
+#endif
 	spin_lock_irqsave(&mtk_crtc->config_lock, flags);
 	mtk_crtc->config_updating = false;
 	spin_unlock_irqrestore(&mtk_crtc->config_lock, flags);
-#endif
 
+update_config_out:
 	mutex_unlock(&mtk_crtc->hw_lock);
 }
 
-- 
2.43.0