Como corrigir o erro xrandr ao tentar criar um novo modo?

Question

Tentativa:

sudo xrandr --newmode 1152x864_60.00   81.75  1152 1216 1336 1520  864 867 871 897 -hsync +vsync

Me dá:

X Error of failed request:  BadName (named color or font does not exist)
  Major opcode of failed request:  140 (RANDR)
  Minor opcode of failed request:  16 (RRCreateMode)
  Serial number of failed request:  43
  Current serial number in output stream:  43