diff --git a/hw/qxl.c b/hw/qxl.c
index 3c82c2a..eb7707c 100644
--- a/hw/qxl.c
+++ b/hw/qxl.c
@@ -1466,7 +1466,7 @@ static void ioport_write(void *opaque, target_phys_addr_t addr,
     }
 
     if (d->revision <= QXL_REVISION_STABLE_V10 &&
-        io_port >= QXL_IO_FLUSH_SURFACES_ASYNC) {
+        io_port > QXL_IO_FLUSH_RELEASE) {
         qxl_set_guest_bug(d, "unsupported io %d for revision %d\n",
             io_port, d->revision);
         return;