I am new in Ubuntu I cannot set my resolution to 1366x768 all options in graphical displays is 1024x768 only. I tried cvt 1366 768 and xrandr --newmode "1368x768_60.00" 85.86 1368 1440 1584 1800 768 769 772 795 -HSync +Vsync and got xrandr: Failed to get size of gamma for output default X Error of failed request: BadName (named color or font does not exist) Major opcode of failed request: 149 (RANDR) Minor opcode of failed request: 16 (RRCreateMode) Serial number of failed request: 19 Current serial number in output stream: 19 What can I do.