CentOS 7 Computers Unable to Increase Resolution above 1920x1200 on New Monitors

General support questions
Post Reply
tenkiforecast
Posts: 5
Joined: 2020/07/26 16:34:03

CentOS 7 Computers Unable to Increase Resolution above 1920x1200 on New Monitors

Post by tenkiforecast » 2021/06/29 20:23:57

All,

Posting due to an issue I have not been able to solve. At my work, we replaced two 10-year-old CentOS 6 machines with new CentOS 7 machines, and moved them into an operational location elsewhere in the building. They are hooked up to monitors owned by another company through DVI inputs for the prior configuration. We were surprised when we hooked up our new CentOS 7 machines, and found that we could not increase the resolution over 1920x1200. I attempted to set the resolution to a higher frame rate, 2560x1600, to no avail. We are using nvidia P600 Quadro graphics cards, which means that any attempt to use 'xrandr' to set resolutions are incompatible with the kmod-nvidia drivers obtained through the elrepo repositories. I was, however, able to use xrandr to gain some information:
Screen 0: minimum 8 x 8, current 1920 x 2400, maximum 32767 x 32767
DP-0 connected primary 1920x1200+0+0 (normal left inverted right x axis y axis) 640mm x 400mm

Screen 0 appears to be the internal display, while DP-0 represents the first of two monitors attached to the machine through DVI to mDP adapters. I attempted to hook up the display with a mDP to HMDI cable to see if I could natively acquire a higher resolution (if the problem was the transition across mdp to DVI converters), and I was not offered any higher resolutions when attempting to change display settings in the GUI applications (In MATE, System > Preferences > Hardware > Displays) or when I opened nvidia-settings. The monitors can support higher resolutions; the CentOS 6 machines output in higher resolutions without a problem, which is why the sudden inability to use higher resolutions was such a surprise. Despite the resolution issues, the computers are functional and have been in place for over a year. Actively addressing why the resolution problems exist was a lower priority due to other factors (including the pandemic).

Looking up various guides, the solution offered was actively changing the xorg.conf file. An exerpt from the file generated by nvidia-settings is below:

Section "Monitor"
Identifier "Monitor0"
VendorName "Unknown"
ModelName "DELL U3011"
HorizSync 29.0 - 113.0
VertRefresh 49.0 - 86.0
EndSection

Section "Device"
Identifier "Videocard0"
Driver "nvidia"
EndSection

Section "Device"
Identifier "Device0"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "Quadro P600"
EndSection

Section "Screen"
Identifier "Default Screen"
Device "Videocard0"
EndSection

Section "Screen"
Identifier "Screen0"
Device "Device0"
Monitor "Monitor0"
DefaultDepth 24
Option "Stereo" "0"
Option "nvidiaXineramaInfoOrder" "DFP-0"
Option "metamodes" "DP-0: 1920x1200 +0+0, DP-2: 1920x1200 +0+1200"
Option "SLI" "Off"
Option "MultiGPU" "Off"
Option "BaseMosaic" "off"
SubSection "Display"
Depth 24
EndSubSection


I don't know how to modify the file past this point. If there are no resolutions offered in nvidia-settings above 1920x1200, then I cannot edit it through a software system and need to go in as admin. In the process of looking up other solutions, I saw mention of installing a kernel labeled "kernel-lm." I would rather not try to change kernels just because of a resolution issue. However, I do not know how to approach addressing the resolution issue from here. Other solutions I found involved changing display managers--I changed from MATE to Cinammon briefly, and encountered the same problems--did not work. Does anyone know how to approach this issue?

Post Reply