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Commit f622a71d authored by Ramalingam C's avatar Ramalingam C Committed by Sean Paul
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drm/i915: Retry HDCP bksv read 



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: default avatarRamalingam C <ramalingam.c@intel.com>
Signed-off-by: default avatarSean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1517851922-30547-1-git-send-email-ramalingam.c@intel.com
parent cb340bf3

drivers/gpu/drm/i915/intel_hdcp.c

+13 −5
Original line number Diff line number Diff line
@@ -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));



	/* 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;

	else if (!intel_hdcp_is_ksv_valid(bksv.shim))

		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]);