linux-kernel - Re: [PATCH v2] drm: bridge: dw_hdmi: Fix ELD is not updated issue

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Date:   Fri, 4 Aug 2023 10:22:55 +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 v2] drm: bridge: dw_hdmi: Fix ELD is not updated issue

On 04/08/2023 08:11, 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>
> 
> ---
> v2:
>    - Add the variable of last_connector_result back to driver.
>      It will only be used to initialize audio codec jack status when audio codec driver probe.
> 
> ---
>   drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 12 +++---------
>   1 file changed, 3 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> index aa51c61a78c7..963050de42c3 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> @@ -2463,15 +2463,7 @@ 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);
> +	hdmi->last_connector_result = result;
>   
>   	return result;
>   }
> @@ -2971,6 +2963,7 @@ 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);
>   }
>   
> @@ -2989,6 +2982,7 @@ 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);
>   }
>   

Reviewed-by: Neil Armstrong <neil.armstrong@...aro.org>