Ubuntu的超宽屏支持2560*1080，参见：

• http://ubuntuhandbook.org/index.php/2017/04/custom-screen-resolution-ubuntu-desktop/

不过，没搞定。

最后，换了根4K线就自动识别了，不要用老的DSP/HDMI线和接口转换器，传输率不够。

后面这些操作都是多余的，而且没有任何效果。

操作：

openthings@openthings:~$ xrandr
Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 32767 x 32767
DP-0 disconnected (normal left inverted right x axis y axis)
DP-1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 670mm x 280mm1920x1080     60.00*+1680x1050     59.95  1600x1200     60.00  1440x900      74.98    59.89  1280x1024     75.02    60.02  1280x720      60.00  1024x768      75.03    60.00  800x600       75.00    60.32  640x480       75.00    72.81    59.94
DP-2 disconnected (normal left inverted right x axis y axis)
DP-3 disconnected (normal left inverted right x axis y axis)
HDMI-0 disconnected (normal left inverted right x axis y axis)
DP-4 disconnected (normal left inverted right x axis y axis)
DP-5 disconnected (normal left inverted right x axis y axis)

计算分辨率参数:

openthings@openthings:~$ cvt 2560 1080
# 2560x1080 59.98 Hz (CVT) hsync: 67.17 kHz; pclk: 230.00 MHz
Modeline "2560x1080_60.00"  230.00  2560 2720 2992 3424  1080 1083 1093 1120 -hsync +vsync

设置：

#添加显示模式
xrandr --newmode "2560x1080_60.00"  230.00  2560 2720 2992 3424  1080 1083 1093 1120 -hsync +vsync
xrandr --addmode DP-1 "2560x1080_60.00"

出错：

openthings@openthings:~$ xrandr --addmode DP-1 "2560x1080_60.00"
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:  41Current serial number in output stream:  42