enum {
        /* Options that take integer arguments */
-       Opt_port, Opt_msize, Opt_uid, Opt_gid, Opt_afid,
+       Opt_debug, Opt_port, Opt_msize, Opt_uid, Opt_gid, Opt_afid,
        Opt_rfdno, Opt_wfdno,
        /* String options */
        Opt_uname, Opt_remotename,
 };
 
 static match_table_t tokens = {
+       {Opt_debug, "debug=%x"},
        {Opt_port, "port=%u"},
        {Opt_msize, "msize=%u"},
        {Opt_uid, "uid=%u"},
                        }
                }
                switch (token) {
+               case Opt_debug:
+                       v9ses->debug = option;
+                       p9_debug_level = option;
+                       break;
                case Opt_port:
                        v9ses->port = option;
                        break;
 
        struct v9fs_session_info *v9ses = mnt->mnt_sb->s_fs_info;
 
        if (v9ses->debug != 0)
-               seq_printf(m, ",debug=%u", v9ses->debug);
+               seq_printf(m, ",debug=%x", v9ses->debug);
        if (v9ses->port != V9FS_PORT)
                seq_printf(m, ",port=%u", v9ses->port);
        if (v9ses->maxdata != 9000)