From: Ramalingam C <ramalingam.c@intel.com>
Date: Mon, 2 Apr 2018 17:20:22 +0530
Subject: drm/i915: Read HDCP R0 thrice in case of mismatch
Git-commit: 4bfbec68966082f046232a011d6f371e8554bb40
Patch-mainline: v4.18-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166
As per DP spec when R0 mismatch is detected, HDCP source supported
re-read the R0 atleast twice.
And For HDMI and DP minimum wait required for the R0 availability is
100mSec. So this patch changes the wait time to 100mSec but retries
twice with the time interval of 100mSec for each attempt.
This patch is needed for DP HDCP1.4 CTS Test: 1A-06.
v2:
No Change
v3:
Comment on R0 retry is moved closer to the code[Seanpaul]
v4:
Removing unwanted noise introduced in v3.
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1522669822-2508-1-git-send-email-ramalingam.c@intel.com
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
drivers/gpu/drm/i915/intel_hdcp.c | 27 +++++++++++++++++++--------
1 file changed, 19 insertions(+), 8 deletions(-)
--- a/drivers/gpu/drm/i915/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/intel_hdcp.c
@@ -506,15 +506,26 @@ static int intel_hdcp_auth(struct intel_
*/
wait_remaining_ms_from_jiffies(r0_prime_gen_start, 300);
- ri.reg = 0;
- ret = shim->read_ri_prime(intel_dig_port, ri.shim);
- if (ret)
- return ret;
- I915_WRITE(PORT_HDCP_RPRIME(port), ri.reg);
+ tries = 3;
- /* Wait for Ri prime match */
- if (wait_for(I915_READ(PORT_HDCP_STATUS(port)) &
- (HDCP_STATUS_RI_MATCH | HDCP_STATUS_ENC), 1)) {
+ /*
+ * DP HDCP Spec mandates the two more reattempt to read R0, incase
+ * of R0 mismatch.
+ */
+ for (i = 0; i < tries; i++) {
+ ri.reg = 0;
+ ret = shim->read_ri_prime(intel_dig_port, ri.shim);
+ if (ret)
+ return ret;
+ I915_WRITE(PORT_HDCP_RPRIME(port), ri.reg);
+
+ /* Wait for Ri prime match */
+ if (!wait_for(I915_READ(PORT_HDCP_STATUS(port)) &
+ (HDCP_STATUS_RI_MATCH | HDCP_STATUS_ENC), 1))
+ break;
+ }
+
+ if (i == tries) {
DRM_ERROR("Timed out waiting for Ri prime match (%x)\n",
I915_READ(PORT_HDCP_STATUS(port)));
return -ETIMEDOUT;