From 4bfbec68966082f046232a011d6f371e8554bb40 Mon Sep 17 00:00:00 2001 From: Ramalingam C Date: Mon, 2 Apr 2018 17:20:22 +0530 Subject: [PATCH] drm/i915: Read HDCP R0 thrice in case of mismatch 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 Reviewed-by: Sean Paul Signed-off-by: Rodrigo Vivi Link: https://patchwork.freedesktop.org/patch/msgid/1522669822-2508-1-git-send-email-ramalingam.c@intel.com --- drivers/gpu/drm/i915/intel_hdcp.c | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c index 14ca5d3057a7..f2cf2e3acd3c 100644 --- 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_digital_port *intel_dig_port, */ 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; -- 2.30.2