Unlisted screen resolution

Question

On my new computer I have 2 screens connected on the igpu of a i7 processor, 1 using hdmi. the other using dvi. Both screens are the same but the one connected using hdmi has a wrong resolution inside X, and it can't be selected inside the settings. How can this be solved?

Solution

first run

$ xrandr

this will give output like this:

Screen 0: minimum 320 x 200, current 5120 x 1080, maximum 8192 x 8192
HDMI1 connected 2560x1080+2560+0 (normal left inverted right x axis y axis) 677mm x 290mm 
   1920x1080     60.00*  
   1680x1050     59.88  
   1600x900      59.98  
...

HDMI2 connected 2560x1080+0+0 (normal left inverted right x axis y axis) 677mm x 290mm
   2560x1080     60.00*+
   2560x1080_60.00  59.98  
   1920x1080     60.00    50.00    59.94    30.00    29.97  
   1920x1080i    60.00    50.00    59.94  
... 

to add 2560x1080 to HDMI1 first run the next command

$ cvt 2560 1080

sample output:

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

now you need to use this output to test the resolution and than add the settings for use in the next sessions.

testing:

$ xrandr --newmode "2560x1080_60.00"  230.00  2560 2720 2992 3424  1080 1083 1093 1120 -hsync +vsync
$ xrandr --addmode HDMI1 2560x1080_60.00
$ xrandr --output HDMI1 --mode 2560x1080_60.00

if it works you can add it to the xorg configuration

$ sudo vim /etc/X11/xorg.conf.d/40-monitor.conf

or

$ sudo vim /usr/share/X11/xorg.conf.d/40-monitor.conf

Section "Monitor"
    Identifier "HDMI1"
    Modeline "2560x1080_60.00"  230.00  2560 2720 2992 3424  1080 1083 1093 1120 -hsync +vsync
    Option "PreferredMode" "2560x1080"
EndSection

Comments

[Admin]

Which one shows "wrong resolution"? Hardware details, in particular maximal resolutions?

[Marcus Johansson]

Is the resolution ment to change when I run --addmode? Or is it going to appear in the display settings? (I am using debian)

[switch87]

It is added to the display settings, you stillbhave to set the resolution.

[rrogers]

Excellent: by that I mean it worked (which is something great). One minor point for me. I had to add video=HDMI-A-1:e

[rrogers]

Excellent: by that I mean, it worked (which is something great). One minor point for me. I had to add video=HDMI-A-1:e to the end of kernel mode settings. I have forgotten where I got that name from; xrandr says HDMI-0 for a name. I still haven't quite got my booting stable but once it boots the above procedure takes hold. My bios doesn't play nice with some versions of X11.

[switch87]

This is the exact same lg display I have, my method works on Nvidia and Intel (only ones I tried on). The problem has nothing to do with the gpu driver, only with the information given to the computer by the display itself

[Amir Qayyum Khan]

Actually this is the only thing that worked for me. And monitor not having anything to do with display driver is just plain wrong mate.

[switch87]

The resolutions given back by the display are co trolled by the display firmware, not by the gpu driver (you do not have a display driver). LG has quite a lot displays with this kind of problems it seems.

[Amir Qayyum Khan]

And the display drivers differ in native drivers and nouveau drivers.

[Amir Qayyum Khan]

Why the negative flags? I just proposed an alternative that worked for me.