linux-kernel - Re: [PATCH v7 2/2] drm/mediatek: Add isolation to edp

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Message-ID: <e9f167c88c29fa30ef3a22995c2955cde478b41d.camel@mediatek.com>
Date: Wed, 17 Dec 2025 10:08:23 +0000
From: CK Hu (胡俊光) <ck.hu@...iatek.com>
To: "simona@...ll.ch" <simona@...ll.ch>, Mac Shen (沈俊)
	<Mac.Shen@...iatek.com>, AngeloGioacchino Del Regno
	<angelogioacchino.delregno@...labora.com>, "chunkuang.hu@...nel.org"
	<chunkuang.hu@...nel.org>, "airlied@...il.com" <airlied@...il.com>,
	Project_Global_Chrome_Upstream_Group
	<Project_Global_Chrome_Upstream_Group@...iatek.com>, "p.zabel@...gutronix.de"
	<p.zabel@...gutronix.de>, "matthias.bgg@...il.com" <matthias.bgg@...il.com>,
	Peng Liu (刘鹏) <Peng.Liu@...iatek.com>,
	LIANKUN YANG (杨连坤) <Liankun.Yang@...iatek.com>
CC: "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
	"linux-mediatek@...ts.infradead.org" <linux-mediatek@...ts.infradead.org>,
	"linux-arm-kernel@...ts.infradead.org"
	<linux-arm-kernel@...ts.infradead.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v7 2/2] drm/mediatek: Add isolation to edp

On Tue, 2025-11-04 at 16:55 +0800, Liankun Yang wrote:
> Because edp doesn't expect any (un)plug events during runtime and
> its process differs from DP. Therefore, it is necessary to isolate
> the parsing capability, panel power, training state and enable state.
> 
> And DP related behaviors are adjusted to execute in the second half
> of the interrupt.
> For DP details, see drm/mediatek: Adjust bandwidth limit for DP
> 
> Signed-off-by: Liankun Yang <liankun.yang@...iatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dp.c | 37 +++++++++++++++----------------
>  1 file changed, 18 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c
> index 0ba2c208811c..efd4c45985ca 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dp.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dp.c
> @@ -2187,7 +2187,8 @@ static const struct drm_edid *mtk_dp_edid_read(struct drm_bridge *bridge,
>  	 * Parse capability here to let atomic_get_input_bus_fmts and
>  	 * mode_valid use the capability to calculate sink bitrates.
>  	 */
> -	if (mtk_dp_parse_capabilities(mtk_dp)) {
> +	if (mtk_dp->bridge.type == DRM_MODE_CONNECTOR_eDP &&
> +	    mtk_dp_parse_capabilities(mtk_dp)) {

This is not related to dp training.
If dp does not need to parse edid, describe WHY and do not mix edid modification with dp training modification.

>  		drm_err(mtk_dp->drm_dev, "Can't parse capabilities\n");
>  		drm_edid_free(drm_edid);
>  		drm_edid = NULL;
> @@ -2385,13 +2386,15 @@ static void mtk_dp_bridge_atomic_enable(struct drm_bridge *bridge,
>  		return;
>  	}
>  
> -	mtk_dp_aux_panel_poweron(mtk_dp, true);
> +	if (mtk_dp->data->bridge_type == DRM_MODE_CONNECTOR_eDP) {
> +		mtk_dp_aux_panel_poweron(mtk_dp, true);
>  
> -	/* Training */
> -	ret = mtk_dp_training(mtk_dp);
> -	if (ret) {
> -		drm_err(mtk_dp->drm_dev, "Training failed, %d\n", ret);
> -		goto power_off_aux;
> +		/* Training */
> +		ret = mtk_dp_training(mtk_dp);
> +		if (ret) {
> +			drm_err(mtk_dp->drm_dev, "Training failed, %d\n", ret);
> +			goto power_off_aux;
> +		}

Merge this to previous patch.

>  	}
>  
>  	ret = mtk_dp_video_config(mtk_dp);
> @@ -2411,7 +2414,9 @@ static void mtk_dp_bridge_atomic_enable(struct drm_bridge *bridge,
>  		       sizeof(mtk_dp->info.audio_cur_cfg));
>  	}
>  
> -	mtk_dp->enabled = true;
> +	if (mtk_dp->data->bridge_type == DRM_MODE_CONNECTOR_eDP)
> +		mtk_dp->enabled = true;

Merge this to previous patch.

> +
>  	mtk_dp_update_plugged_status(mtk_dp);
>  
>  	return;
> @@ -2426,21 +2431,15 @@ static void mtk_dp_bridge_atomic_disable(struct drm_bridge *bridge,
>  {
>  	struct mtk_dp *mtk_dp = mtk_dp_from_bridge(bridge);
>  
> -	mtk_dp->enabled = false;
> +	if (mtk_dp->data->bridge_type == DRM_MODE_CONNECTOR_eDP) {
> +		mtk_dp->enabled = false;

Merge this to previous patch.

> +		mtk_dp_aux_panel_poweron(mtk_dp, false);

You change the code flow of DRM_MODE_CONNECTOR_eDP.
I think you should not change this.

> +	}
> +
>  	mtk_dp_update_plugged_status(mtk_dp);
>  	mtk_dp_video_enable(mtk_dp, false);
>  	mtk_dp_audio_mute(mtk_dp, true);
>  
> -	if (mtk_dp->train_info.cable_plugged_in) {
> -		drm_dp_dpcd_writeb(&mtk_dp->aux, DP_SET_POWER, DP_SET_POWER_D3);
> -		usleep_range(2000, 3000);

For DRM_MODE_CONNECTOR_DP, you remove this usleep. This may cause side effect.
Doesn't it?

> -	}
> -
> -	/* power off aux */
> -	mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
> -			   DP_PWR_STATE_BANDGAP_TPLL,
> -			   DP_PWR_STATE_MASK);

if (mtk_dp->data->bridge_type == DRM_MODE_CONNECTOR_eDP) {
	/* power off aux */
	mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
			   DP_PWR_STATE_BANDGAP_TPLL,
			   DP_PWR_STATE_MASK);
}

Regards,
CK

> -
>  	/* SDP path reset sw*/
>  	mtk_dp_sdp_path_reset(mtk_dp);
>