drm/i915: dont retry stream management at seq_num_m roll over

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@intel.com>
Reviewed-by: Anshuman Gupta <anshuman.gupta@intel.com> [v3]
Tested-by: Anshuman Gupta <anshuman.gupta@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200923132435.17039-3-anshuman.gupta@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
index d750bb5..b2a4bbc 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
@@ -1448,7 +1448,6 @@ static
 int _hdcp2_propagate_stream_management_info(struct intel_connector *connector)
 {
        struct intel_digital_port *dig_port = intel_attached_dig_port(connector);
-       struct drm_i915_private *i915 = to_i915(connector->base.dev);
        struct intel_hdcp *hdcp = &connector->hdcp;
        union {
                struct hdcp2_rep_stream_manage stream_manage;
@@ -1457,6 +1456,9 @@ 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);
@@ -1485,10 +1487,6 @@ 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_dbg_kms(&i915->drm, "seq_num_m roll over.\n");
-               return -ERANGE;
-       }
 
        return ret;
 }
@@ -1699,6 +1697,13 @@ 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);