linux-kernel - [PATCH v2 2/3] drm/mediatek: Add pm_runtime support for GCE power control

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Message-ID: <20250829091727.3745415-3-jason-jh.lin@mediatek.com>
Date: Fri, 29 Aug 2025 17:15:59 +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>, Jassi Brar
	<jassisinghbrar@...il.com>, Mauro Carvalho Chehab <mchehab@...nel.org>
CC: Philipp Zabel <p.zabel@...gutronix.de>, David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>, Jason-JH Lin <jason-jh.lin@...iatek.com>,
	Nancy Lin <nancy.lin@...iatek.com>, Singo Chang <singo.chang@...iatek.com>,
	Paul-PL Chen <paul-pl.chen@...iatek.com>, Yongqiang Niu
	<yongqiang.niu@...iatek.com>, Zhenxing Qin <zhenxing.qin@...iatek.com>,
	Xiandong Wang <xiandong.wang@...iatek.com>, Sirius Wang
	<sirius.wang@...iatek.com>, Xavier Chang <xavier.chang@...iatek.com>, Jarried
 Lin <jarried.lin@...iatek.com>, Fei Shao <fshao@...omium.org>, Chen-yu Tsai
	<wenst@...omium.org>, <Project_Global_Chrome_Upstream_Group@...iatek.com>,
	<dri-devel@...ts.freedesktop.org>, <linux-mediatek@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>, <linux-arm-kernel@...ts.infradead.org>,
	<linux-media@...r.kernel.org>
Subject: [PATCH v2 2/3] drm/mediatek: Add pm_runtime support for GCE power control

Call pm_runtime_resume_and_get() before accessing GCE hardware in
mbox_send_message(), and invoke pm_runtime_put_autosuspend() in the
cmdq callback to release the PM reference and start autosuspend for
GCE. This ensures correct power management for the GCE device.

Fixes: 8afe816b0c99 ("mailbox: mtk-cmdq-mailbox: Implement Runtime PM with autosuspend")
Signed-off-by: Jason-JH Lin <jason-jh.lin@...iatek.com>
---
 drivers/gpu/drm/mediatek/mtk_crtc.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_crtc.c b/drivers/gpu/drm/mediatek/mtk_crtc.c
index bc7527542fdc..c4c6d0249df5 100644
--- a/drivers/gpu/drm/mediatek/mtk_crtc.c
+++ b/drivers/gpu/drm/mediatek/mtk_crtc.c
@@ -283,6 +283,10 @@ static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg)
 	unsigned int i;
 	unsigned long flags;
 
+	/* release GCE HW usage and start autosuspend */
+	pm_runtime_mark_last_busy(cmdq_cl->chan->mbox->dev);
+	pm_runtime_put_autosuspend(cmdq_cl->chan->mbox->dev);
+
 	if (data->sta < 0)
 		return;
 
@@ -618,6 +622,9 @@ static void mtk_crtc_update_config(struct mtk_crtc *mtk_crtc, bool needs_vblank)
 		mtk_crtc->config_updating = false;
 		spin_unlock_irqrestore(&mtk_crtc->config_lock, flags);
 
+		if (pm_runtime_resume_and_get(mtk_crtc->cmdq_client.chan->mbox->dev) < 0)
+			goto update_config_out;
+
 		mbox_send_message(mtk_crtc->cmdq_client.chan, cmdq_handle);
 		mbox_client_txdone(mtk_crtc->cmdq_client.chan, 0);
 		goto update_config_out;
-- 
2.43.0