On Mon, Apr 02, 2018 at 05:20:22PM +0530, Ramalingam C wrote:
> 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 <ramalinga...@intel.com>
Reviewed-by: Sean Paul <seanp...@chromium.org>
> ---
> 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;
> --
> 2.7.4
>
--
Sean Paul, Software Engineer, Google / Chromium OS
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