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

Sean Paul
2018-02-02T14:45:11Z

On Fri, Feb 02, 2018 at 07:52:24PM +0530, Ramalingam C wrote:
>
>
> On Friday 02 February 2018 07:39 PM, Sean Paul wrote:
> > 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.
> Yes. Thought about that option too. Actually I would prefer having the
> reference of intel_connector untill generic hdcp auth implementation.
> we can pass the intel digital port for encoder specific shims.
>
> This will help me with
>     providing the connector details for state transitions as in next patches
>     next steps like SRM passing in for revocation and downstream topology
> gathering (perhaps will start with availability of complementing user space)
>
> At this point if we dont want this code, I will disable hdcp from enable
> functions.

Yes please. Let's not try to predict the future and keep things as simple as
possible.

Sean

>
> -Ram
> >
> >
> > > + 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