Re: [PATCH 1/8] drm/i915: Handle failure from 2nd stage HDCP auth

Sean Paul
2018-02-02T14:09:51Z

On Fri, Feb 02, 2018 at 04:15:13PM +0530, Ramalingam C wrote:
> We enable the HDCP encryption as a part of first stage authentication.
> So when second stage authentication fails, we need to disable the HDCP
> encryption and signalling.
>
> This patch handles above requirement.
>
> For reusing the _intel_hdcp_disable from generic authentication flow,
> this patch retain the reference to connector till the generic hdcp flow.
> This will be handy to provide the connector details in HDCP enable
> debug info.
>
> Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
> ---
> drivers/gpu/drm/i915/intel_hdcp.c | 41 +++++++++++++++++++++++----------------
> 1 file changed, 24 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c
> index b97184eccd9c..0021511ae4d7 100644
> --- a/drivers/gpu/drm/i915/intel_hdcp.c
> +++ b/drivers/gpu/drm/i915/intel_hdcp.c
> @@ -16,6 +16,8 @@
>
> #define KEY_LOAD_TRIES 5
>
> +static int _intel_hdcp_disable(struct intel_connector *connector);
> +
> static int intel_hdcp_poll_ksv_fifo(struct intel_digital_port *intel_dig_port,
> const struct intel_hdcp_shim *shim)
> {
> @@ -138,17 +140,24 @@ bool intel_hdcp_is_ksv_valid(u8 *ksv)
> return true;
> }
>
> +static
> +struct intel_digital_port *conn_to_dig_port(struct intel_connector *connector)
> +{
> + return enc_to_dig_port(&connector->encoder->base);
> +}
> +
> /* Implements Part 2 of the HDCP authorization procedure */
> static
> -int intel_hdcp_auth_downstream(struct intel_digital_port *intel_dig_port,
> - const struct intel_hdcp_shim *shim)
> +int intel_hdcp_auth_downstream(struct intel_connector *connector)
> {
> struct drm_i915_private *dev_priv;
> u32 vprime, sha_text, sha_leftovers, rep_ctl;
> u8 bstatus[2], num_downstream, *ksv_fifo;
> int ret, i, j, sha_idx;
> + const struct intel_hdcp_shim *shim = connector->hdcp_shim;
> + struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
>
> - dev_priv = intel_dig_port->base.base.dev->dev_private;
> + dev_priv = to_i915(connector->base.dev);
>
> ret = intel_hdcp_poll_ksv_fifo(intel_dig_port, shim);
> if (ret) {
> @@ -385,8 +394,7 @@ int intel_hdcp_auth_downstream(struct intel_digital_port *intel_dig_port,
> }
>
> /* Implements Part 1 of the HDCP authorization procedure */
> -static int intel_hdcp_auth(struct intel_digital_port *intel_dig_port,
> - const struct intel_hdcp_shim *shim)
> +static int intel_hdcp_auth(struct intel_connector *connector)
> {
> struct drm_i915_private *dev_priv;
> enum port port;
> @@ -405,9 +413,10 @@ static int intel_hdcp_auth(struct intel_digital_port *intel_dig_port,
> u8 shim[DRM_HDCP_RI_LEN];
> } ri;
> bool repeater_present;
> + const struct intel_hdcp_shim *shim = connector->hdcp_shim;
> + struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
>
> - dev_priv = intel_dig_port->base.base.dev->dev_private;
> -
> + dev_priv = to_i915(connector->base.dev);
> port = intel_dig_port->base.port;
>
> /* Initialize An with 2 random values and acquire it */
> @@ -498,19 +507,18 @@ static int intel_hdcp_auth(struct intel_digital_port *intel_dig_port,
> * on those as well.
> */
>
> - if (repeater_present)
> - return intel_hdcp_auth_downstream(intel_dig_port, shim);
> + if (repeater_present) {
> + ret = intel_hdcp_auth_downstream(connector);
> + if (ret) {
> + _intel_hdcp_disable(connector);

If you just call this from _intel_hdcp_enable when intel_hdcp_auth() fails, you
can avoid all of this code, it'd just be one line.

> + return ret;
> + }
> + }
>
> DRM_DEBUG_KMS("HDCP is enabled (no repeater present)\n");
> return 0;
> }
>
> -static
> -struct intel_digital_port *conn_to_dig_port(struct intel_connector *connector)
> -{
> - return enc_to_dig_port(&intel_attached_encoder(&connector->base)->base);
> -}
> -
> static int _intel_hdcp_disable(struct intel_connector *connector)
> {
> struct drm_i915_private *dev_priv = connector->base.dev->dev_private;
> @@ -558,8 +566,7 @@ static int _intel_hdcp_enable(struct intel_connector *connector)
> return ret;
> }
>
> - ret = intel_hdcp_auth(conn_to_dig_port(connector),
> - connector->hdcp_shim);
> + ret = intel_hdcp_auth(connector);
> if (ret) {
> DRM_ERROR("Failed to authenticate HDCP (%d)\n", ret);
> return ret;
> --
> 2.7.4
>

--
Sean Paul, Software Engineer, Google / Chromium OS