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@mediatek.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

Jason-JH Lin <jason-jh.lin@mediatek.com> 於 2025年8月29日 週五 上午9:17寫道：
>
> 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.

Applied to mediatek-drm-fixes [1], thanks.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/log/?h=mediatek-drm-fixes

Regards,
Chun-Kuang.

>
> Fixes: 8afe816b0c99 ("mailbox: mtk-cmdq-mailbox: Implement Runtime PM with autosuspend")
> Signed-off-by: Jason-JH Lin <jason-jh.lin@mediatek.com>
> ---

On Fri, 2025-08-29 at 17:15 +0800, Jason-JH Lin wrote:
> 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.

Reviewed-by: CK Hu <ck.hu@mediatek.com>

> 
> Fixes: 8afe816b0c99 ("mailbox: mtk-cmdq-mailbox: Implement Runtime PM with autosuspend")
> Signed-off-by: Jason-JH Lin <jason-jh.lin@mediatek.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;