diff --git a/sys/dev/drm2/ttm/ttm_page_alloc.c b/sys/dev/drm2/ttm/ttm_page_alloc.c
index ffc8483a398..9a30a4640e6 100644
--- a/sys/dev/drm2/ttm/ttm_page_alloc.c
+++ b/sys/dev/drm2/ttm/ttm_page_alloc.c
@@ -113,16 +113,22 @@ struct ttm_pool_manager {
 	struct ttm_pool_opts	options;
 
 	union {
-		struct ttm_page_pool	pools[NUM_POOLS];
-		struct {
-			struct ttm_page_pool	wc_pool;
-			struct ttm_page_pool	uc_pool;
-			struct ttm_page_pool	wc_pool_dma32;
-			struct ttm_page_pool	uc_pool_dma32;
-		} ;
-	};
+		struct ttm_page_pool	u_pools[NUM_POOLS];
+		struct _utag {
+			struct ttm_page_pool	u_wc_pool;
+			struct ttm_page_pool	u_uc_pool;
+			struct ttm_page_pool	u_wc_pool_dma32;
+			struct ttm_page_pool	u_uc_pool_dma32;
+		} _ut;
+	} _u;
 };
 
+#define	pools _u.u_pools
+#define	wc_pool _u._ut.u_wc_pool
+#define	uc_pool _u._ut.u_uc_pool
+#define	wc_pool_dma32 _u._ut.u_wc_pool_dma32
+#define	uc_pool_dma32 _u._ut.u_uc_pool_dma32
+
 MALLOC_DEFINE(M_TTM_POOLMGR, "ttm_poolmgr", "TTM Pool Manager");
 
 static void