[PATCH 11/22] drm/amd/display: Workaround to do HDCP authentication twice on certain displays

[Rodrigo Siqueira]

From: George Shen <george.shen at amd.com>

[Why]
When transitioning from SST to MST, the HDCP repeater in some MST
displays will enter a bad state. The HDCP repeater is recovered after
failing and performing authentication again.

[How]
Add monitor patch to trigger HDCP authentication failure after
encryption is enabled and re-authenticate.

Signed-off-by: George Shen <george.shen at amd.com>
Reviewed-by: Wenjing Liu <Wenjing.Liu at amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira at amd.com>
---
 drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_transition.c | 3 +++
 drivers/gpu/drm/amd/display/modules/inc/mod_hdcp.h          | 3 ++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_transition.c b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_transition.c
index 5bc6706d2af7..f3711914364e 100644
--- a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_transition.c
+++ b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_transition.c
@@ -230,6 +230,9 @@ enum mod_hdcp_status mod_hdcp_hdcp1_dp_transition(struct mod_hdcp *hdcp,
 				(!conn->is_repeater && is_dp_mst_hdcp(hdcp) && input->stream_encryption_dp != PASS)) {
 			fail_and_restart_in_ms(0, &status, output);
 			break;
+		} else if (conn->hdcp1_retry_count < conn->link.adjust.hdcp1.min_auth_retries_wa) {
+			fail_and_restart_in_ms(0, &status, output);
+			break;
 		}
 		if (conn->is_repeater) {
 			set_watchdog_in_ms(hdcp, 5000, output);
diff --git a/drivers/gpu/drm/amd/display/modules/inc/mod_hdcp.h b/drivers/gpu/drm/amd/display/modules/inc/mod_hdcp.h
index 891bca555e17..bb855ea5d5a3 100644
--- a/drivers/gpu/drm/amd/display/modules/inc/mod_hdcp.h
+++ b/drivers/gpu/drm/amd/display/modules/inc/mod_hdcp.h
@@ -157,7 +157,8 @@ struct mod_hdcp_display_adjustment {
 struct mod_hdcp_link_adjustment_hdcp1 {
 	uint8_t disable			: 1;
 	uint8_t postpone_encryption	: 1;
-	uint8_t reserved		: 6;
+	uint8_t min_auth_retries_wa : 1;
+	uint8_t reserved		: 5;
 };
 
 enum mod_hdcp_force_hdcp_type {
-- 
2.25.1