linux-kernel - Re: [PATCH v4 1/5] drm/bridge: cadence: cdns-mhdp8546-core: Remove legacy support for connector initialisation in bridge

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Message-ID: <zur4q7hcb2jujfxowrhoh7sxzkawadv4oe6vuemb75xnajq6gb@ti7hhpt3fb5m>
Date: Fri, 1 Aug 2025 14:01:36 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Jayesh Choudhary <j-choudhary@...com>
Cc: andrzej.hajda@...el.com, neil.armstrong@...aro.org, rfoss@...nel.org,
        Laurent.pinchart@...asonboard.com, mripard@...nel.org,
        lumag@...nel.org, dianders@...omium.org,
        dri-devel@...ts.freedesktop.org, tomi.valkeinen@...asonboard.com,
        jonas@...boo.se, jernej.skrabec@...il.com,
        maarten.lankhorst@...ux.intel.com, tzimmermann@...e.de,
        airlied@...il.com, simona@...ll.ch, lyude@...hat.com,
        luca.ceresoli@...tlin.com, viro@...iv.linux.org.uk,
        andy.yan@...k-chips.com, linux@...blig.org, javierm@...hat.com,
        linux-kernel@...r.kernel.org, devarsht@...com
Subject: Re: [PATCH v4 1/5] drm/bridge: cadence: cdns-mhdp8546-core: Remove
 legacy support for connector initialisation in bridge

On Tue, Jun 24, 2025 at 11:14:44AM +0530, Jayesh Choudhary wrote:
> Now that we have DBANC framework, remove the connector initialisation code
> as that piece of code is not called if DRM_BRIDGE_ATTACH_NO_CONNECTOR flag
> is used. Only TI K3 platforms consume this driver and tidss (their display
> controller) has this flag set. So this legacy support can be dropped.
> 
> Fixes: c932ced6b585 ("drm/tidss: Update encoder/bridge chain connect model")
> Signed-off-by: Jayesh Choudhary <j-choudhary@...com>
> ---
>  .../drm/bridge/cadence/cdns-mhdp8546-core.c   | 187 +-----------------
>  1 file changed, 10 insertions(+), 177 deletions(-)
> 

> -
> -static int cdns_mhdp_connector_atomic_check(struct drm_connector *conn,
> -					    struct drm_atomic_state *state)
> -{
> -	struct cdns_mhdp_device *mhdp = connector_to_mhdp(conn);
> -	struct drm_connector_state *old_state, *new_state;
> -	struct drm_crtc_state *crtc_state;
> -	u64 old_cp, new_cp;
> -
> -	if (!mhdp->hdcp_supported)
> -		return 0;
> -
> -	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;
> -		goto mode_changed;
> -	}
> -
> -	if (!new_state->crtc) {
> -		if (old_cp == DRM_MODE_CONTENT_PROTECTION_ENABLED)
> -			new_state->content_protection = DRM_MODE_CONTENT_PROTECTION_DESIRED;
> -		return 0;
> -	}

This is the only place which handled disabling of HDCP while disabling the connector.

> -
> -	if (old_cp == new_cp ||
> -	    (old_cp == DRM_MODE_CONTENT_PROTECTION_DESIRED &&
> -	     new_cp == DRM_MODE_CONTENT_PROTECTION_ENABLED))
> -		return 0;
> -
> -mode_changed:
> -	crtc_state = drm_atomic_get_new_crtc_state(state, new_state->crtc);
> -	crtc_state->mode_changed = true;
> -
> -	return 0;
> -}
> -

-- 
With best wishes
Dmitry