Есть монитор Iiyama ProLite XU82792QSU подключенный по HDMI к GeForce GT 610 дрова припроетарные
Через xrandr добавил новый мод
$ xrandr ^_^
Screen 0: minimum 8 x 8, current 3968 x 1280, maximum 16384 x 16384
DVI-I-0 disconnected (normal left inverted right x axis y axis)
VGA-0 connected primary 1920x1080+2048+200 (normal left inverted right x axis y axis) 477mm x 268mm
1920x1080 60.00*+
1680x1050 59.95
1280x1024 75.02 60.02
1152x864 75.00
1024x768 75.03 60.00
800x600 75.00 60.32
640x480 75.00 59.94
DVI-I-1 disconnected (normal left inverted right x axis y axis)
HDMI-0 connected 2048x1280+0+0 (normal left inverted right x axis y axis) 600mm x 340mm
2048x1280 60.00*+
1920x1200 59.88
1920x1080 60.00 59.94 50.00 60.05 60.00 50.04
1680x1050 59.95
1600x1200 60.00
1600x900 60.00
1440x900 59.89
1280x1024 75.02
1280x720 60.00 59.94 50.00
1024x768 75.03 60.00
800x600 75.00 60.32
720x576 50.00
720x480 59.94
640x480 75.00 59.94 59.93
2560x1440_59.90 (0x2d1) 311.310MHz -HSync +VSync
h: width 2560 start 2744 end 3024 total 3488 skew 0 clock 89.25KHz
v: height 1440 start 1441 end 1444 total 1490 clock 59.90Hz
$ xrandr --addmode HDMI-0 "2560x1440_59.90" ^_^
X Error of failed request: BadMatch (invalid parameter attributes)
Major opcode of failed request: 140 (RANDR)
Minor opcode of failed request: 18 (RRAddOutputMode)
Serial number of failed request: 31
Current serial number in output stream: 32
Xorg config https://gist.github.com/balamyt92/54af0d0c0540ee41b6d3bb29cb4c5277