Adding the following lines to the "Device" section,
Option "UseFBDev" "false" Option "MonitorLayout" "TMDS,NONE"
and the following ModeLine to the "Monitor" section:
Modeline "1360x768" 84.50 1360 1392 1712 1744 768 783 791 807
makes 1360x768 work OK.
Adding the following lines to the "Device" section,
Option "UseFBDev" "false"
Option "MonitorLayout" "TMDS,NONE"
and the following ModeLine to the "Monitor" section:
Modeline "1360x768" 84.50 1360 1392 1712 1744 768 783 791 807
makes 1360x768 work OK.