diff --git a/src/emu/pv/prv.c b/src/emu/pv/prv.c
index e4bd3dd..9e57429 100644
--- a/src/emu/pv/prv.c
+++ b/src/emu/pv/prv.c
@@ -99,10 +99,6 @@ emit(struct prv *prv, struct prv_chan *rchan)
 			if (rchan->flags & PRV_SKIPDUP)
 				return 0;
 
-			int is_null = value_is_null(value);
-			if (rchan->flags & PRV_SKIPNULL && is_null)
-				return 0;
-
 			err("error duplicated value %s for channel %s\n",
 					value_str(value), chan->name);
 			return -1;
diff --git a/src/emu/pv/prv.h b/src/emu/pv/prv.h
index 86af7f7..b289729 100644
--- a/src/emu/pv/prv.h
+++ b/src/emu/pv/prv.h
@@ -14,9 +14,8 @@ struct prv;
 enum prv_flags {
 	PRV_EMITDUP  = 1<<0, /* Emit duplicates (no error, emit) */
 	PRV_SKIPDUP  = 1<<1, /* Skip duplicates (no error, no emit) */
-	PRV_SKIPNULL = 1<<2, /* Skip null duplicates (no error, no emit) */
-	PRV_NEXT     = 1<<3, /* Add one to the channel value */
-	PRV_ZERO     = 1<<4, /* Value 0 is allowed */
+	PRV_NEXT     = 1<<2, /* Add one to the channel value */
+	PRV_ZERO     = 1<<3, /* Value 0 is allowed */
 };
 
 struct prv_chan {