diff mbox

[v4,1/4] drm/i915: Read HDCP R0 thrice in case of mismatch

Message ID 1522669822-2508-1-git-send-email-ramalingam.c@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Ramalingam C April 2, 2018, 11:50 a.m. UTC
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>
---
 drivers/gpu/drm/i915/intel_hdcp.c | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)

Comments

Sean Paul April 2, 2018, 1:49 p.m. UTC | #1
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 <ramalingam.c@intel.com>

Reviewed-by: Sean Paul <seanpaul@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
>
diff mbox

Patch

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;