(gdb) run
Starting program: /usr/bin/mutter 
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/usr/lib/libthread_db.so.1".
X Error of failed request:  BadValue (integer parameter out of range for operation)
  Major opcode of failed request:  131 (XInputExtension)
  Minor opcode of failed request:  57 ()
  Value in failed request:  0x12d
  Serial number of failed request:  258
  Current serial number in output stream:  259
[Thread 0x7ffff7f56940 (LWP 1072) exited]
[Inferior 1 (process 1072) exited with code 01]