linux-kernel - Re: [PATCH] drm: bridge: dw_hdmi: Fix ELD is not updated issue

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Message-ID: <743b7abb-127d-49c1-f863-1a7d388b8166@linaro.org>
Date:   Tue, 1 Aug 2023 11:36:15 +0200
From:   neil.armstrong@...aro.org
To:     Sandor Yu <Sandor.yu@....com>, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org
Cc:     andrzej.hajda@...el.com, rfoss@...nel.org,
        Laurent.pinchart@...asonboard.com, jonas@...boo.se,
        jernej.skrabec@...il.com, adrian.larumbe@...labora.com,
        treding@...dia.com, the.cheaterman@...il.com,
        l.stach@...gutronix.de, ville.syrjala@...ux.intel.com,
        cychiang@...omium.org, shengjiu.wang@....com
Subject: Re: [PATCH] drm: bridge: dw_hdmi: Fix ELD is not updated issue

Hi,

On 26/07/2023 03:48, Sandor Yu wrote:
> The ELD (EDID-Like Data) is not updated when the HDMI cable
> is plugged into different HDMI monitors.
> This is because the EDID is not updated in the HDMI HPD function.
> As a result, the ELD data remains unchanged and may not reflect
> the capabilities of the newly connected HDMI sink device.
> 
> To address this issue, the handle_plugged_change function should move to
> the bridge_atomic_enable and bridge_atomic_disable functions.
> Make sure the EDID is properly updated before updating ELD.
> 
> Signed-off-by: Sandor Yu <Sandor.yu@....com>
> ---
>   drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 21 ++++-----------------
>   1 file changed, 4 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> index 9a3db5234a0e0..6fa4848591226 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> @@ -196,7 +196,6 @@ struct dw_hdmi {
>   
>   	hdmi_codec_plugged_cb plugged_cb;
>   	struct device *codec_dev;
> -	enum drm_connector_status last_connector_result;
>   };
>   
>   #define HDMI_IH_PHY_STAT0_RX_SENSE \
> @@ -235,7 +234,7 @@ int dw_hdmi_set_plugged_cb(struct dw_hdmi *hdmi, hdmi_codec_plugged_cb fn,
>   	mutex_lock(&hdmi->mutex);
>   	hdmi->plugged_cb = fn;
>   	hdmi->codec_dev = codec_dev;
> -	plugged = hdmi->last_connector_result == connector_status_connected;
> +	plugged = hdmi->connector.status == connector_status_connected;

Please use curr_conn instead, connector is not always valid.

>   	handle_plugged_change(hdmi, plugged);
>   	mutex_unlock(&hdmi->mutex);
>   
> @@ -2446,20 +2445,7 @@ static void dw_hdmi_update_phy_mask(struct dw_hdmi *hdmi)
>   
>   static enum drm_connector_status dw_hdmi_detect(struct dw_hdmi *hdmi)
>   {
> -	enum drm_connector_status result;
> -
> -	result = hdmi->phy.ops->read_hpd(hdmi, hdmi->phy.data);
> -
> -	mutex_lock(&hdmi->mutex);
> -	if (result != hdmi->last_connector_result) {
> -		dev_dbg(hdmi->dev, "read_hpd result: %d", result);
> -		handle_plugged_change(hdmi,
> -				      result == connector_status_connected);
> -		hdmi->last_connector_result = result;
> -	}
> -	mutex_unlock(&hdmi->mutex);
> -
> -	return result;
> +	return hdmi->phy.ops->read_hpd(hdmi, hdmi->phy.data);
>   }
>   
>   static struct edid *dw_hdmi_get_edid(struct dw_hdmi *hdmi,
> @@ -2958,6 +2944,7 @@ static void dw_hdmi_bridge_atomic_disable(struct drm_bridge *bridge,
>   	hdmi->curr_conn = NULL;
>   	dw_hdmi_update_power(hdmi);
>   	dw_hdmi_update_phy_mask(hdmi);
> +	handle_plugged_change(hdmi, false);
>   	mutex_unlock(&hdmi->mutex);
>   }
>   
> @@ -2976,6 +2963,7 @@ static void dw_hdmi_bridge_atomic_enable(struct drm_bridge *bridge,
>   	hdmi->curr_conn = connector;
>   	dw_hdmi_update_power(hdmi);
>   	dw_hdmi_update_phy_mask(hdmi);
> +	handle_plugged_change(hdmi, true);
>   	mutex_unlock(&hdmi->mutex);
>   }
>   
> @@ -3369,7 +3357,6 @@ struct dw_hdmi *dw_hdmi_probe(struct platform_device *pdev,
>   	hdmi->rxsense = true;
>   	hdmi->phy_mask = (u8)~(HDMI_PHY_HPD | HDMI_PHY_RX_SENSE);
>   	hdmi->mc_clkdis = 0x7f;
> -	hdmi->last_connector_result = connector_status_disconnected;
>   
>   	mutex_init(&hdmi->mutex);
>   	mutex_init(&hdmi->audio_mutex);

Thanks,
Neil