drm/amd/display: save restore hdcp state when display is unplugged from mst hub

[Why]
connector hdcp properties are lost after display is
unplgged from mst hub. connector is destroyed with
dm_dp_mst_connector_destroy. when display is plugged
back, hdcp is not desired and it wouldnt be enabled.

[How]
save hdcp properties into hdcp_work within
amdgpu_dm_atomic_commit_tail. If the same display is
plugged back with same display index, its hdcp
properties will be retrieved from hdcp_work within
dm_dp_mst_get_modes.
Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: hersen wu <hersenxs.wu@amd.com>
Reviewed-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -8310,11 +8310,33 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
 			continue;
 		}
 
-		if (is_content_protection_different(new_con_state, old_con_state, connector, adev->dm.hdcp_workqueue))
+		if (is_content_protection_different(new_con_state, old_con_state, connector, adev->dm.hdcp_workqueue)) {
+			/* when display is unplugged from mst hub, connctor will
+			 * be destroyed within dm_dp_mst_connector_destroy. connector
+			 * hdcp perperties, like type, undesired, desired, enabled,
+			 * will be lost. So, save hdcp properties into hdcp_work within
+			 * amdgpu_dm_atomic_commit_tail. if the same display is
+			 * plugged back with same display index, its hdcp properties
+			 * will be retrieved from hdcp_work within dm_dp_mst_get_modes
+			 */
+
+			if (aconnector->dc_link && aconnector->dc_sink &&
+				aconnector->dc_link->type == dc_connection_mst_branch) {
+				struct hdcp_workqueue *hdcp_work = adev->dm.hdcp_workqueue;
+				struct hdcp_workqueue *hdcp_w =
+					&hdcp_work[aconnector->dc_link->link_index];
+
+				hdcp_w->hdcp_content_type[connector->index] =
+					new_con_state->hdcp_content_type;
+				hdcp_w->content_protection[connector->index] =
+					new_con_state->content_protection;
+			}
+
 			hdcp_update_display(
 				adev->dm.hdcp_workqueue, aconnector->dc_link->link_index, aconnector,
 				new_con_state->hdcp_content_type,
 				new_con_state->content_protection == DRM_MODE_CONTENT_PROTECTION_DESIRED);
+    }
 	}
 #endif
 

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.h

@@ -52,6 +52,20 @@ struct hdcp_workqueue {
 	struct mod_hdcp_link link;
 
 	enum mod_hdcp_encryption_status encryption_status;
+
+	/* when display is unplugged from mst hub, connctor will be
+	 * destroyed within dm_dp_mst_connector_destroy. connector
+	 * hdcp perperties, like type, undesired, desired, enabled,
+	 * will be lost. So, save hdcp properties into hdcp_work within
+	 * amdgpu_dm_atomic_commit_tail. if the same display is
+	 * plugged back with same display index, its hdcp properties
+	 * will be retrieved from hdcp_work within dm_dp_mst_get_modes
+	 */
+	/* un-desired, desired, enabled */
+	unsigned int content_protection[AMDGPU_DM_MAX_DISPLAY_INDEX];
+	/* hdcp1.x, hdcp2.x */
+	unsigned int hdcp_content_type[AMDGPU_DM_MAX_DISPLAY_INDEX];
+
 	uint8_t max_link;
 
 	uint8_t *srm;

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c

@@ -32,6 +32,10 @@
 #include "amdgpu_dm.h"
 #include "amdgpu_dm_mst_types.h"
 
+#ifdef CONFIG_DRM_AMD_DC_HDCP
+#include "amdgpu_dm_hdcp.h"
+#endif
+
 #include "dc.h"
 #include "dm_helpers.h"
 
@@ -344,6 +348,28 @@ static int dm_dp_mst_get_modes(struct drm_connector *connector)
 		/* dc_link_add_remote_sink returns a new reference */
 		aconnector->dc_sink = dc_sink;
 
+		/* when display is unplugged from mst hub, connctor will be
+		 * destroyed within dm_dp_mst_connector_destroy. connector
+		 * hdcp perperties, like type, undesired, desired, enabled,
+		 * will be lost. So, save hdcp properties into hdcp_work within
+		 * amdgpu_dm_atomic_commit_tail. if the same display is
+		 * plugged back with same display index, its hdcp properties
+		 * will be retrieved from hdcp_work within dm_dp_mst_get_modes
+		 */
+#ifdef CONFIG_DRM_AMD_DC_HDCP
+		if (aconnector->dc_sink && connector->state) {
+			struct drm_device *dev = connector->dev;
+			struct amdgpu_device *adev = drm_to_adev(dev);
+			struct hdcp_workqueue *hdcp_work = adev->dm.hdcp_workqueue;
+			struct hdcp_workqueue *hdcp_w = &hdcp_work[aconnector->dc_link->link_index];
+
+			connector->state->hdcp_content_type =
+			hdcp_w->hdcp_content_type[connector->index];
+			connector->state->content_protection =
+			hdcp_w->content_protection[connector->index];
+		}
+#endif
+
 		if (aconnector->dc_sink) {
 			amdgpu_dm_update_freesync_caps(
 					connector, aconnector->edid);