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

[CK Hu (胡俊光)]

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 at mediatek.com>

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