linux-kernel - Re: [PATCH v3 9/9] drm/i915: Implement HDCP for DisplayPort

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Message-ID: <49e69878-1fcf-1d46-218c-28cae11c7def@intel.com>
Date:   Tue, 5 Dec 2017 20:00:57 +0530
From:   Ramalingam C <ramalingam.c@...el.com>
To:     Sean Paul <seanpaul@...omium.org>, dri-devel@...ts.freedesktop.org,
        intel-gfx@...ts.freedesktop.org
Cc:     seanpaul@...gle.com, David Airlie <airlied@...ux.ie>,
        Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
        linux-kernel@...r.kernel.org,
        Rodrigo Vivi <rodrigo.vivi@...el.com>, daniel.vetter@...el.com
Subject: Re: [PATCH v3 9/9] drm/i915: Implement HDCP for DisplayPort



On Tuesday 05 December 2017 10:45 AM, Sean Paul wrote:
> +static
> +bool intel_dp_hdcp_check_link(struct intel_digital_port *intel_dig_port)
> +{
> +	ssize_t ret;
> +	u8 bstatus;
> +	ret = drm_dp_dpcd_read(&intel_dig_port->dp.aux, DP_AUX_HDCP_BSTATUS,
> +			       &bstatus, 1);
> +	if (ret != 1) {
> +		DRM_ERROR("Read bstatus from DP/AUX failed (%ld)\n", ret);
> +		return ret >= 0 ? -EIO : ret;
> +	}
> +	return !(bstatus & DP_BSTATUS_LINK_FAILURE);
> +}
as per link integrity check should cover other indication from the 
repeater like

REAUTHENTICATION_REQUEST - request for reauth due to unauthenticated 
state at downstream for some unknown reason

-Ram