How to change resolution without xrandr

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friolator
Posts: 1
Joined: 2022/09/08 21:05:32

How to change resolution without xrandr

Post by friolator » 2022/09/08 21:10:48

We have a CentOS 7 machine that runs DaVinci Resolve Studio. We recently upgraded Resolve to the newest version, which forced an nvidia driver update, which changed something on this machine that had been working fine for years. The GUI monitor for Resolve is connected to a Raritan KVM switch which has a resolution of 1680x1050. Previously, we would get the login screen on boot, and once logged in a shell script would change the resolution to 1680x1050. Worked fine. However, we're no longer seeing the login screen now, it goes black. With the KVM switch, this generally happens when the computer is outputting the wrong video resolution or refresh rate.

So I would like to force it to 1680x1050 @ 60Hz, but I'm not sure where. I can ssh into this machine but when I try to run xrandr, which is what comes up in every.single.google.search, i get an error that there's no display connected, so I'm at a dead end. Is there any way to do this manually, and if so can someone post step by step instructions or link me to something that will actually work?

Code: Select all

[root@localhost /]# xrandr
Can't open display 

Thanks!

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TrevorH
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Location: Brighton, UK

Re: How to change resolution without xrandr

Post by TrevorH » 2022/09/09 12:56:03

Read the man page for xrandr. There are switches to tell it what display to operate against. You're running it as root and I hope that you are not logging in as root to run this app. You are logging in as a normal user and then opening a root command prompt (sudo?) to attempt to run xrandr? If so then none of the correct environment variables are set to say what the display should be.

In any case I'm not sure this is the right solution to your problem. You might want to read https://ask.fedoraproject.org/t/how-to- ... ktop/11982 and see if the solution there helps you. You could also look at https://wiki.archlinux.org/title/GDM from somewhere about the section titled "Setup default monitor settings" onwards.
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

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