diff --git a/ttynvt.c b/ttynvt.c
index c00856e..6594b5f 100644
--- a/ttynvt.c
+++ b/ttynvt.c
@@ -529,6 +529,36 @@ static int baudrate(speed_t speed)
 
 static const char pstr[] = { ' ', 'N', 'O', 'E', 'M', 'S' };
 
+#define CASE(name) case name: return #name
+
+static const char *_ioctl_name(int cmd)
+{
+    static char     buf[16];
+
+    switch (cmd)
+    {
+    default:
+        snprintf(buf, sizeof(buf), "0x%x", cmd);
+        return buf;
+        CASE(TCSETSF);
+        CASE(TCSETSW);
+        CASE(TCSETS);
+        CASE(TCGETS);
+        CASE(TIOCINQ);
+        CASE(TIOCOUTQ);
+        CASE(TCFLSH);
+        CASE(TCIFLUSH);
+        CASE(TCOFLUSH);
+        CASE(TCIOFLUSH);
+        CASE(TIOCMGET);
+        CASE(TIOCMBIS);
+        CASE(TIOCMBIC);
+        CASE(TIOCMSET);
+        CASE(TCSBRK);
+        CASE(TIOCGWINSZ);
+    }
+}
+
 static void
 ttynvt_ioctl(fuse_req_t req, int cmd, void *arg,
              struct fuse_file_info *info, unsigned int flags,
@@ -542,6 +572,10 @@ ttynvt_ioctl(fuse_req_t req, int cmd, void *arg,
     };
     int             val;
 
+    DBG("%s: cmd=%s arg=%p ibuf=%p:%u obuf=:%u\n", __func__,
+        _ioctl_name(cmd), arg, in_buf,
+        (unsigned int)in_bufsz, (unsigned int)out_bufsz);
+
     switch (cmd)
     {
     case TCSETSF: