[Intel-gfx] [PATCH v3 2/2] drm/i915: dont retry stream management at seq_num_m roll over

[Ramalingam C]

When roll over detected for seq_num_m, we shouldn't continue with stream
management with rolled over value.

So we are terminating the stream management retry, on roll over of the
seq_num_m.

v2:
  using drm_dbg_kms instead of DRM_DEBUG_KMS [Anshuman]
v3:
  dev_priv is used as i915 [JaniN]
v4:
  roll over is detected at the start of the stream management.

Signed-off-by: Ramalingam C <ramalingam.c at intel.com>
Reviewed-by: Anshuman Gupta <anshuman.gupta at intel.com> [v3]
Tested-by: Anshuman Gupta <anshuman.gupta at intel.com>
---
 drivers/gpu/drm/i915/display/intel_hdcp.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
index 85e1e8cf16c7..7b470502feaa 100644
--- a/drivers/gpu/drm/i915/display/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
@@ -1399,6 +1399,9 @@ int _hdcp2_propagate_stream_management_info(struct intel_connector *connector)
 	const struct intel_hdcp_shim *shim = hdcp->shim;
 	int ret;
 
+	if (connector->hdcp.seq_num_m > HDCP_2_2_SEQ_NUM_MAX)
+		return -ERANGE;
+
 	/* Prepare RepeaterAuth_Stream_Manage msg */
 	msgs.stream_manage.msg_id = HDCP_2_2_REP_STREAM_MANAGE;
 	drm_hdcp_cpu_to_be24(msgs.stream_manage.seq_num_m, hdcp->seq_num_m);
@@ -1427,11 +1430,6 @@ int _hdcp2_propagate_stream_management_info(struct intel_connector *connector)
 
 out:
 	hdcp->seq_num_m++;
-	if (hdcp->seq_num_m > HDCP_2_2_SEQ_NUM_MAX) {
-		DRM_DEBUG_KMS("seq_num_m roll over.\n");
-		ret = -ERANGE;
-	}
-
 	return ret;
 }
 
@@ -1639,6 +1637,13 @@ hdcp2_propagate_stream_management_info(struct intel_connector *connector)
 		if (!ret)
 			break;
 
+		/* Lets restart the auth incase of seq_num_m roll over */
+		if (connector->hdcp.seq_num_m > HDCP_2_2_SEQ_NUM_MAX) {
+			drm_dbg_kms(&i915->drm,
+				    "seq_num_m roll over.(%d)\n", ret);
+			break;
+		}
+
 		drm_dbg_kms(&i915->drm,
 			    "HDCP2 stream management %d of %d Failed.(%d)\n",
 			    i + 1, tries, ret);
-- 
2.20.1