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@intel.com --- 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: /* 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; }