diff --git a/sndiod/siofile.c b/sndiod/siofile.c
index a624614..eb40528 100644
--- a/sndiod/siofile.c
+++ b/sndiod/siofile.c
@@ -353,7 +353,8 @@ dev_sio_run(void *arg)
 			n = sio_read(d->sio.hdl, data, d->sio.todo);
 			d->sio.todo -= n;
 #ifdef DEBUG
-			if (n == 0 && data == base && !sio_eof(d->sio.hdl)) {
+			if (log_level >= 3 &&
+			    n == 0 && data == base && !sio_eof(d->sio.hdl)) {
 				dev_log(d);
 				log_puts(": read blocked at cycle start\n");
 			}
@@ -436,7 +437,8 @@ dev_sio_run(void *arg)
 			n = sio_write(d->sio.hdl, data, d->sio.todo);
 			d->sio.todo -= n;
 #ifdef DEBUG
-			if (n == 0 && data == base && !sio_eof(d->sio.hdl)) {
+			if (log_level >= 3 &&
+			    n == 0 && data == base && !sio_eof(d->sio.hdl)) {
 				dev_log(d);
 				log_puts(": write blocked at cycle start\n");
 			}