On Mon, Feb 26, 2018 at 10:42:36PM +0530, Ramalingam C wrote:
> In case of V prime mismatch, DP HDCP spec mandates the re-read of
> Vprime atleast twice.
>
> DP HDCP CTS Test: 1B-05
>
> Signed-off-by: Ramalingam C <ramalingam.c@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/intel_hdcp.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c
> index 730681d2dbfb..7ea55fa46f41 100644
> --- a/drivers/gpu/drm/i915/intel_hdcp.c
> +++ b/drivers/gpu/drm/i915/intel_hdcp.c
> @@ -150,7 +150,7 @@ int intel_hdcp_auth_downstream(struct intel_digital_port *intel_dig_port,
> 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;
> + int ret, i, j, sha_idx, tries = 3;
>
> dev_priv = intel_dig_port->base.base.dev->dev_private;
>
> @@ -189,6 +189,7 @@ int intel_hdcp_auth_downstream(struct intel_digital_port *intel_dig_port,
> if (ret)
> return ret;
>
> +read_v_prime:
Instead of using the label for retry, please break it out into a function that's
enclosed in a retry loop.
Sean
> /* Process V' values from the receiver */
> for (i = 0; i < DRM_HDCP_V_PRIME_NUM_PARTS; i++) {
> ret = shim->read_v_prime_part(intel_dig_port, i, &vprime);
> @@ -385,6 +386,13 @@ int intel_hdcp_auth_downstream(struct intel_digital_port *intel_dig_port,
> return -ETIMEDOUT;
> }
> if (!(I915_READ(HDCP_REP_CTL) & HDCP_SHA1_V_MATCH)) {
> +
> + /*
> + * When V prime mismatches, DP Spec mandates re-read of
> + * V prime atleast twice.
> + */
> + if (--tries)
> + goto read_v_prime;
> DRM_ERROR("SHA-1 mismatch, HDCP failed\n");
> return -ENXIO;
> }
> --
> 2.7.4
>
--
Sean Paul, Software Engineer, Google / Chromium OS
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