drm/amd/display: force CP to DESIRED when removing display

[WHY]
- Commit from userspace could cause link stream to disable and hdcp
auth to reset when the HDCP has already been enabled at the moment.
CP should fall back to DESIRED from ENABLED in such cases.
- This change was previously reverted due to a regression caused, which
has now been cleared.

[HOW]
In hdcp display removal, change CP to DESIRED if at the moment CP
is ENABLED before the auth reset and removal of linked list element.
Signed-off-by: Dingchen (David) Zhang <dingchen.zhang@amd.com>
Signed-off-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Acked-by: Stylon Wang <stylon.wang@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_hdcp.c

@@ -222,10 +222,23 @@ static void hdcp_remove_display(struct hdcp_workqueue *hdcp_work,
 			 struct amdgpu_dm_connector *aconnector)
 {
 	struct hdcp_workqueue *hdcp_w = &hdcp_work[link_index];
+	struct drm_connector_state *conn_state = aconnector->base.state;
 
 	mutex_lock(&hdcp_w->mutex);
 	hdcp_w->aconnector = aconnector;
 
+	/* the removal of display will invoke auth reset -> hdcp destroy and
+	 * we'd expect the Content Protection (CP) property changed back to
+	 * DESIRED if at the time ENABLED. CP property change should occur
+	 * before the element removed from linked list.
+	 */
+	if (conn_state && conn_state->content_protection == DRM_MODE_CONTENT_PROTECTION_ENABLED) {
+		conn_state->content_protection = DRM_MODE_CONTENT_PROTECTION_DESIRED;
+
+		DRM_DEBUG_DRIVER("[HDCP_DM] display %d, CP 2 -> 1, type %u, DPMS %u\n",
+			 aconnector->base.index, conn_state->hdcp_content_type, aconnector->base.dpms);
+	}
+
 	mod_hdcp_remove_display(&hdcp_w->hdcp, aconnector->base.index, &hdcp_w->output);
 
 	process_output(hdcp_w);
@@ -469,7 +482,7 @@ static void update_config(void *handle, struct cp_psp_stream_config *config)
 	link->adjust.hdcp1.disable = 0;
 	conn_state = aconnector->base.state;
 
-	pr_debug("[HDCP_DM] display %d, CP %d, type %d\n", aconnector->base.index,
+	DRM_DEBUG_DRIVER("[HDCP_DM] display %d, CP %d, type %d\n", aconnector->base.index,
 			(!!aconnector->base.state) ? aconnector->base.state->content_protection : -1,
 			(!!aconnector->base.state) ? aconnector->base.state->hdcp_content_type : -1);