linux-kernel - Re: [PATCH RESEND v9 3/6] drm/bridge: cadence: cdns-mhdp8546-core: Handle HDCP state in bridge atomic check

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Message-ID: <b6e44d61-7704-48fa-ba03-ba1a75e8a4f8@ideasonboard.com>
Date: Fri, 21 Nov 2025 14:46:45 +0200
From: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
To: Harikrishna Shenoy <h-shenoy@...com>
Cc: Laurent.pinchart@...asonboard.com, airlied@...il.com,
 andrzej.hajda@...el.com, andy.yan@...k-chips.com, aradhya.bhatia@...ux.dev,
 devarsht@...com, dianders@...omium.org, dri-devel@...ts.freedesktop.org,
 javierm@...hat.com, jernej.skrabec@...il.com, jonas@...boo.se,
 linux-kernel@...r.kernel.org, linux@...blig.org, luca.ceresoli@...tlin.com,
 lumag@...nel.org, lyude@...hat.com, maarten.lankhorst@...ux.intel.com,
 mordan@...ras.ru, mripard@...nel.org, neil.armstrong@...aro.org,
 rfoss@...nel.org, s-jain1@...com, simona@...ll.ch, tzimmermann@...e.de,
 u-kumar1@...com
Subject: Re: [PATCH RESEND v9 3/6] drm/bridge: cadence: cdns-mhdp8546-core:
 Handle HDCP state in bridge atomic check

Hi,

On 20/11/2025 14:14, Harikrishna Shenoy wrote:
> Now that we have DRM_BRIDGE_ATTACH_NO_CONNECTOR framework, handle the
> HDCP state change inbridge atomic check as well to enable correct

"in bridge's"

> functioning for HDCP in both DRM_BRIDGE_ATTACH_NO_CONNECTOR and
> !DRM_BRIDGE_ATTACH_NO_CONNECTOR case.

Same thing here. What is the issue? What behavior do you see without
this patch?

 Tomi

> Fixes: 6a3608eae6d33 ("drm: bridge: cdns-mhdp8546: Enable HDCP")
> Signed-off-by: Harikrishna Shenoy <h-shenoy@...com>
> ---
>  .../drm/bridge/cadence/cdns-mhdp8546-core.c   | 23 +++++++++++++++++++
>  1 file changed, 23 insertions(+)
> 
> diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
> index 7178a01e4d4d8..d944095da4722 100644
> --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
> +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
> @@ -2123,6 +2123,10 @@ static int cdns_mhdp_atomic_check(struct drm_bridge *bridge,
>  {
>  	struct cdns_mhdp_device *mhdp = bridge_to_mhdp(bridge);
>  	const struct drm_display_mode *mode = &crtc_state->adjusted_mode;
> +	struct drm_connector_state *old_state, *new_state;
> +	struct drm_atomic_state *state = crtc_state->state;
> +	struct drm_connector *conn = mhdp->connector_ptr;
> +	u64 old_cp, new_cp;
>  
>  	mutex_lock(&mhdp->link_mutex);
>  
> @@ -2142,6 +2146,25 @@ static int cdns_mhdp_atomic_check(struct drm_bridge *bridge,
>  	if (mhdp->info)
>  		bridge_state->input_bus_cfg.flags = *mhdp->info->input_bus_flags;
>  
> +	if (conn && mhdp->hdcp_supported) {
> +		old_state = drm_atomic_get_old_connector_state(state, conn);
> +		new_state = drm_atomic_get_new_connector_state(state, conn);
> +		old_cp = old_state->content_protection;
> +		new_cp = new_state->content_protection;
> +
> +		if (old_state->hdcp_content_type != new_state->hdcp_content_type &&
> +		    new_cp != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
> +			new_state->content_protection = DRM_MODE_CONTENT_PROTECTION_DESIRED;
> +			crtc_state = drm_atomic_get_new_crtc_state(state, new_state->crtc);
> +			crtc_state->mode_changed = true;
> +		}
> +
> +		if (!new_state->crtc) {
> +			if (old_cp == DRM_MODE_CONTENT_PROTECTION_ENABLED)
> +				new_state->content_protection = DRM_MODE_CONTENT_PROTECTION_DESIRED;
> +		}
> +	}
> +
>  	mutex_unlock(&mhdp->link_mutex);
>  	return 0;
>  }