linux-kernel - Re: [PATCH v3] drm/bridge:anx7625: Update HDCP status at atomic

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Message-ID: <vkrl7om7hepboovp2uivcnernia3ygqwrj3y3kkjydeclwvrk5@7tkdc4etkcjs>
Date: Thu, 12 Dec 2024 11:18:18 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Xin Ji <xji@...logixsemi.com>
Cc: Andrzej Hajda <andrzej.hajda@...el.com>, 
	Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, 
	Laurent Pinchart <Laurent.pinchart@...asonboard.com>, Jonas Karlman <jonas@...boo.se>, 
	Jernej Skrabec <jernej.skrabec@...il.com>, Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
	Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, bliang@...logixsemi.com, 
	qwen@...logixsemi.com, treapking@...gle.com, dri-devel@...ts.freedesktop.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] drm/bridge:anx7625: Update HDCP status at
 atomic_enable()

On Thu, Dec 12, 2024 at 01:51:10PM +0800, Xin Ji wrote:
> When user enabled HDCP feature, userspace will set HDCP content
> to DRM_MODE_CONTENT_PROTECTION_DESIRED. Next, anx7625 will update
> HDCP content to DRM_MODE_CONTENT_PROTECTION_ENABLED if down stream
> support HDCP feature.
> 
> However once HDCP content turn to DRM_MODE_CONTENT_PROTECTION_ENABLED
> userspace will not update the HDCP content to
> DRM_MODE_CONTENT_PROTECTION_UNDESIRED until monitor disconnect.

It seems you've ingored a part of the previous review comment. It's the
userspace who triggers the ENABLED -> UNDESIRED transition, not the
kernel side. The change to move HDCP handling to atomic_enable() looks
fine, the change to disable HDCP is not (unless I misunderstand
something).

> 
> So, anx7625 driver move hdcp content value checking from bridge
> interface .atomic_check() to .atomic_enable(), then update hdcp content
> according from currently HDCP status. And also disabled HDCP in bridge
> interface .atomic_disable().
> 
> Signed-off-by: Xin Ji <xji@...logixsemi.com>
> ---
>  drivers/gpu/drm/bridge/analogix/anx7625.c | 74 ++++++++++++++---------
>  1 file changed, 46 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
> index a2675b121fe4..f96ce5665e8d 100644
> --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> @@ -861,6 +861,22 @@ static int anx7625_hdcp_disable(struct anx7625_data *ctx)
>  				 TX_HDCP_CTRL0, ~HARD_AUTH_EN & 0xFF);
>  }
>  
> +static void anx7625_hdcp_disable_and_update_cp(struct anx7625_data *ctx)
> +{
> +	struct device *dev = ctx->dev;
> +
> +	if (!ctx->connector)
> +		return;
> +
> +	anx7625_hdcp_disable(ctx);
> +
> +	ctx->hdcp_cp = DRM_MODE_CONTENT_PROTECTION_UNDESIRED;
> +	drm_hdcp_update_content_protection(ctx->connector,
> +					   ctx->hdcp_cp);
> +
> +	dev_dbg(dev, "update CP to UNDESIRE\n");
> +}
> +
>  static int anx7625_hdcp_enable(struct anx7625_data *ctx)
>  {
>  	u8 bcap;
> @@ -2149,34 +2165,6 @@ static int anx7625_connector_atomic_check(struct anx7625_data *ctx,
>  	if (cp == ctx->hdcp_cp)
>  		return 0;
>  
> -	if (cp == DRM_MODE_CONTENT_PROTECTION_DESIRED) {
> -		if (ctx->dp_en) {
> -			dev_dbg(dev, "enable HDCP\n");
> -			anx7625_hdcp_enable(ctx);
> -
> -			queue_delayed_work(ctx->hdcp_workqueue,
> -					   &ctx->hdcp_work,
> -					   msecs_to_jiffies(2000));
> -		}
> -	}
> -
> -	if (cp == DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
> -		if (ctx->hdcp_cp != DRM_MODE_CONTENT_PROTECTION_ENABLED) {
> -			dev_err(dev, "current CP is not ENABLED\n");
> -			return -EINVAL;
> -		}
> -		anx7625_hdcp_disable(ctx);
> -		ctx->hdcp_cp = DRM_MODE_CONTENT_PROTECTION_UNDESIRED;
> -		drm_hdcp_update_content_protection(ctx->connector,
> -						   ctx->hdcp_cp);
> -		dev_dbg(dev, "update CP to UNDESIRE\n");
> -	}
> -
> -	if (cp == DRM_MODE_CONTENT_PROTECTION_ENABLED) {
> -		dev_err(dev, "Userspace illegal set to PROTECTION ENABLE\n");
> -		return -EINVAL;
> -	}
> -
>  	return 0;
>  }
>  
> @@ -2425,6 +2413,8 @@ static void anx7625_bridge_atomic_enable(struct drm_bridge *bridge,
>  	struct anx7625_data *ctx = bridge_to_anx7625(bridge);
>  	struct device *dev = ctx->dev;
>  	struct drm_connector *connector;
> +	struct drm_connector_state *conn_state;
> +	int cp;
>  
>  	dev_dbg(dev, "drm atomic enable\n");
>  
> @@ -2439,6 +2429,32 @@ static void anx7625_bridge_atomic_enable(struct drm_bridge *bridge,
>  	_anx7625_hpd_polling(ctx, 5000 * 100);
>  
>  	anx7625_dp_start(ctx);
> +
> +	conn_state = drm_atomic_get_new_connector_state(state->base.state, connector);
> +
> +	if (WARN_ON(!conn_state))
> +		return;
> +
> +	cp = conn_state->content_protection;
> +	if (cp == DRM_MODE_CONTENT_PROTECTION_DESIRED) {
> +		if (ctx->dp_en) {
> +			dev_dbg(dev, "enable HDCP\n");
> +			anx7625_hdcp_enable(ctx);
> +
> +			queue_delayed_work(ctx->hdcp_workqueue,
> +					   &ctx->hdcp_work,
> +					   msecs_to_jiffies(2000));
> +		}
> +	}
> +
> +	if (cp == DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
> +		if (ctx->hdcp_cp != DRM_MODE_CONTENT_PROTECTION_ENABLED) {
> +			dev_err(dev, "current CP is not ENABLED\n");
> +			return;
> +		}
> +
> +		anx7625_hdcp_disable_and_update_cp(ctx);
> +	}
>  }
>  
>  static void anx7625_bridge_atomic_disable(struct drm_bridge *bridge,
> @@ -2449,6 +2465,8 @@ static void anx7625_bridge_atomic_disable(struct drm_bridge *bridge,
>  
>  	dev_dbg(dev, "drm atomic disable\n");
>  
> +	anx7625_hdcp_disable_and_update_cp(ctx);
> +
>  	ctx->connector = NULL;
>  	anx7625_dp_stop(ctx);
>  
> -- 
> 2.25.1
> 

-- 
With best wishes
Dmitry