backend/drm: move restore logic to drm.c

We'll need to use a bunch of internal functions from that file in
the next commits.

backend/drm/backend.c

@@ -95,24 +95,6 @@ struct wlr_backend *wlr_drm_backend_get_parent(struct wlr_backend *backend) {
 	return drm->parent ? &drm->parent->backend : NULL;
 }
 
-static void build_current_connector_state(struct wlr_output_state *state,
-		struct wlr_drm_connector *conn) {
-	bool enabled = conn->status != DRM_MODE_DISCONNECTED && conn->output.enabled;
-
-	wlr_output_state_init(state);
-	wlr_output_state_set_enabled(state, enabled);
-	if (!enabled) {
-		return;
-	}
-
-	if (conn->output.current_mode != NULL) {
-		wlr_output_state_set_mode(state, conn->output.current_mode);
-	} else {
-		wlr_output_state_set_custom_mode(state,
-			conn->output.width, conn->output.height, conn->output.refresh);
-	}
-}
-
 static void handle_session_active(struct wl_listener *listener, void *data) {
 	struct wlr_drm_backend *drm =
 		wl_container_of(listener, drm, session_active);
@@ -125,26 +107,7 @@ static void handle_session_active(struct wl_listener *listener, void *data) {
 	}
 
 	scan_drm_connectors(drm, NULL);
-
-	// The previous DRM master leaves KMS in an undefined state. We need
-	// to restore out own state, but be careful to avoid invalid
-	// configurations. The connector/CRTC mapping may have changed, so
-	// first disable all CRTCs, then light up the ones we were using
-	// before the VT switch.
-	// TODO: better use the atomic API to improve restoration after a VT switch
-	if (!drm->iface->reset(drm)) {
-		wlr_log(WLR_ERROR, "Failed to reset state after VT switch");
-	}
-
-	struct wlr_drm_connector *conn;
-	wl_list_for_each(conn, &drm->connectors, link) {
-		struct wlr_output_state state;
-		build_current_connector_state(&state, conn);
-		if (!drm_connector_commit_state(conn, &state)) {
-			wlr_drm_conn_log(conn, WLR_ERROR, "Failed to restore state after VT switch");
-		}
-		wlr_output_state_finish(&state);
-	}
+	restore_drm_device(drm);
 }
 
 static void handle_dev_change(struct wl_listener *listener, void *data) {

backend/drm/drm.c

@@ -766,7 +766,7 @@ bool drm_connector_supports_vrr(struct wlr_drm_connector *conn) {
 	return true;
 }
 
-bool drm_connector_commit_state(struct wlr_drm_connector *conn,
+static bool drm_connector_commit_state(struct wlr_drm_connector *conn,
 		const struct wlr_output_state *base) {
 	struct wlr_drm_backend *drm = conn->backend;
 
@@ -1720,6 +1720,46 @@ void scan_drm_leases(struct wlr_drm_backend *drm) {
 	drmFree(list);
 }
 
+static void build_current_connector_state(struct wlr_output_state *state,
+		struct wlr_drm_connector *conn) {
+	bool enabled = conn->status != DRM_MODE_DISCONNECTED && conn->output.enabled;
+
+	wlr_output_state_init(state);
+	wlr_output_state_set_enabled(state, enabled);
+	if (!enabled) {
+		return;
+	}
+
+	if (conn->output.current_mode != NULL) {
+		wlr_output_state_set_mode(state, conn->output.current_mode);
+	} else {
+		wlr_output_state_set_custom_mode(state,
+			conn->output.width, conn->output.height, conn->output.refresh);
+	}
+}
+
+void restore_drm_device(struct wlr_drm_backend *drm) {
+	// The previous DRM master leaves KMS in an undefined state. We need
+	// to restore out own state, but be careful to avoid invalid
+	// configurations. The connector/CRTC mapping may have changed, so
+	// first disable all CRTCs, then light up the ones we were using
+	// before the VT switch.
+	// TODO: better use the atomic API to improve restoration after a VT switch
+	if (!drm->iface->reset(drm)) {
+		wlr_log(WLR_ERROR, "Failed to reset state after VT switch");
+	}
+
+	struct wlr_drm_connector *conn;
+	wl_list_for_each(conn, &drm->connectors, link) {
+		struct wlr_output_state state;
+		build_current_connector_state(&state, conn);
+		if (!drm_connector_commit_state(conn, &state)) {
+			wlr_drm_conn_log(conn, WLR_ERROR, "Failed to restore state after VT switch");
+		}
+		wlr_output_state_finish(&state);
+	}
+}
+
 static int mhz_to_nsec(int mhz) {
 	return 1000000000000LL / mhz;
 }

include/backend/drm/drm.h

@@ -185,10 +185,9 @@ void finish_drm_resources(struct wlr_drm_backend *drm);
 void scan_drm_connectors(struct wlr_drm_backend *state,
 	struct wlr_device_hotplug_event *event);
 void scan_drm_leases(struct wlr_drm_backend *drm);
+void restore_drm_device(struct wlr_drm_backend *drm);
 int handle_drm_event(int fd, uint32_t mask, void *data);
 void destroy_drm_connector(struct wlr_drm_connector *conn);
-bool drm_connector_commit_state(struct wlr_drm_connector *conn,
-	const struct wlr_output_state *state);
 bool drm_connector_is_cursor_visible(struct wlr_drm_connector *conn);
 bool drm_connector_supports_vrr(struct wlr_drm_connector *conn);
 size_t drm_crtc_get_gamma_lut_size(struct wlr_drm_backend *drm,