[PATCH] drm/i915/hdcp: Add the loop only for DP encoders

[Suraj Kandpal]

Add the loop on the first read and write only for DP/DPMST encoders
as this issue is only observed here no need to burden other
encoders with extra retries.

Fixes: 9d5a05f86d2f ("drm/i915/hdcp: Retry first read and writes to downstream")
Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
---
 drivers/gpu/drm/i915/display/intel_hdcp.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
index ed6aa87403e2..fcfb5a9f303a 100644
--- a/drivers/gpu/drm/i915/display/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
@@ -1503,6 +1503,8 @@ static int hdcp2_deauthenticate_port(struct intel_connector *connector)
 static int hdcp2_authentication_key_exchange(struct intel_connector *connector)
 {
 	struct intel_display *display = to_intel_display(connector);
+	struct intel_digital_port *dig_port =
+		intel_attached_dig_port(connector);
 	struct intel_hdcp *hdcp = &connector->hdcp;
 	union {
 		struct hdcp2_ake_init ake_init;
@@ -1513,12 +1515,18 @@ static int hdcp2_authentication_key_exchange(struct intel_connector *connector)
 	} msgs;
 	const struct intel_hdcp_shim *shim = hdcp->shim;
 	size_t size;
-	int ret, i;
+	int ret, i, max_retries;
 
 	/* Init for seq_num */
 	hdcp->seq_num_v = 0;
 	hdcp->seq_num_m = 0;
 
+	if (intel_encoder_is_dp(&dig_port->base) ||
+	    intel_encoder_is_mst(&dig_port->base))
+		max_retries = 10;
+	else
+		max_retries = 1;
+
 	ret = hdcp2_prepare_ake_init(connector, &msgs.ake_init);
 	if (ret < 0)
 		return ret;
@@ -1536,7 +1544,7 @@ static int hdcp2_authentication_key_exchange(struct intel_connector *connector)
 	 * authentication. The values of 10 and delay of 50ms was decided based
 	 * on multiple trial and errors.
 	 */
-	for (i = 0; i < 10; i++) {
+	for (i = 0; i < max_retries; i++) {
 		if (!intel_hdcp2_get_capability(connector)) {
 			msleep(50);
 			continue;
-- 
2.34.1