HDCP specification says that when bksv is identified as invalid
(not with 20 1s), bksv should be re-read and verified.
This patch adds the above mentioned re-read for bksv.
v2:
Rephrased the commit msg [Seanpaul]
v3:
do-while to for-loop [Seanpaul]
v4:
retry only if bksv is invalid and no error msg on each attempt
[Seanpaul]
v5:
Correcting the return value [Seanpaul].
Signed-off-by: Ramalingam C <ramalingam.c@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_hdcp.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c
index cfd13ee8c534..d7ddd6b28cd7 100644
--- a/drivers/gpu/drm/i915/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/intel_hdcp.c
@@ -397,7 +397,7 @@ static int intel_hdcp_auth(struct intel_digital_port *intel_dig_port,
struct drm_i915_private *dev_priv;
enum port port;
unsigned long r0_prime_gen_start;
- int ret, i;
+ int ret, i, tries = 2;
union {
u32 reg[2];
u8 shim[DRM_HDCP_AN_LEN];
@@ -438,11 +438,19 @@ static int intel_hdcp_auth(struct intel_digital_port *intel_dig_port,
r0_prime_gen_start = jiffies;
memset(&bksv, 0, sizeof(bksv));
- ret = shim->read_bksv(intel_dig_port, bksv.shim);
- if (ret)
- return ret;
- else if (!intel_hdcp_is_ksv_valid(bksv.shim))
+
+ /* HDCP spec states that we must retry the bksv if it is invalid */
+ for (i = 0; i < tries; i++) {
+ ret = shim->read_bksv(intel_dig_port, bksv.shim);
+ if (ret)
+ return ret;
+ if (intel_hdcp_is_ksv_valid(bksv.shim))
+ break;
+ }
+ if (i == tries) {
+ DRM_ERROR("HDCP failed, Bksv is invalid\n");
return -ENODEV;
+ }
I915_WRITE(PORT_HDCP_BKSVLO(port), bksv.reg[0]);
I915_WRITE(PORT_HDCP_BKSVHI(port), bksv.reg[1]);
--
2.7.4
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