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I am running with 2 external monitors, one by HDMI the other by VGA. The monitor that is causing trouble is the VGA one. But are the same model, and both work with HDMI. However when I plug in the VGA cable, the monitor loads at 1024x768. Using xrandr and cvt I set a new mode for 1920x1080.

cvt 1920 1080 60
# 1920x1080 59.96 Hz (CVT 2.07M9) hsync: 67.16 kHz; pclk: 173.00 MHz
Modeline "1920x1080_60.00"  173.00  1920 2048 2248 2576  1080 1083 1088 1120 -hsync +vsync
xrandr --newmode "1920x1080_60.00"  173.00  1920 2048 2248 2576  1080 
1083 1088 1120 -hsync +vsync
xrandr --addmode DP2 1920x1080_60.00
xrandr --output DP2 --mode 1920x1080_60.00

Monitor reloads with the following error:

Frequency out of range: 68.5 KHz / 59.8 Hz. Please change the display mode to 1920 x 1080.

I have tried with Gnome, XFCE and i3 all get the same issue. In Gnome and XFCE display GUI the monitor is shown as "Unknown Display". Also tried multiple VGA cables, and swapped the monitors, whichever is VGA has a low resolution, HDMI works totally fine.

An example of my xrandr after running the above commands

Edit: Laptop is Thinkpad E560. Should it say DP1/2 or VGA? I have seen examples where it shows VGA.
Edit 2: Possible solution using http://xtiming.sourceforge.net/cgi-bin/xtiming.pl with everything blank except refresh rate at 60Hz and resolution at 1920x1080 with interlace. I managed to get it working by adding the mode it suggests.
Any possible issues with this?

  • Look into /var/log/Xorg.0.log and find out the EDID information for the monitor that comes via VGA. This contains the maximum possible horizontal and vertical frequencies, so check if your attempted resolution is possible in the first place. Just because your monitor supports a higher resolution over HDMI (digital) doesn't mean that this resolution is also available via VGA (analog) ... – dirkt Oct 19 '17 at 11:07

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