KVM switch ate my display confguration

Getting your soundcard to work, using Debian on non-i386 hardware, etc

KVM switch ate my display confguration

Postby JackMcslay » 2018-03-12 13:57

I've had to use a KVM switch for a while in order to manage another computer and ever since my debian is unable to properly detect the correct resolution of my monitor, maxing out at 1024x768 instead of 1920x1080 that was working fine before that.

So far the only workaround is using xrandr with --newmode and --addmode to manually add the entry but I can't find a permanent solution
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Re: KVM switch ate my display confguration

Postby bw123 » 2018-03-12 15:36

I haven't always had good luck with autodetection either. Sometimes it's a bad cable, sometimes the monitor can seem to lose it, sometimes it's a misconfiguration or a stray xorg.conf or snippet left over somewhere. Sometimes it seems to be a driver issue or the display device.

There are different ways you could try to deal with it. I think with a desktop environment it is best to use that tool, whatever it is. With a window manager, the recommended way seems to be xrandr like you mention. You could script it to run as autostart by whatever method is available. Depends on the windowmanager or the desktop.

I still prefer to use a fixed snippet in /etc/X11/xorg.conf.d to add modelines in Section "Monitor" for broken edid/ddc.
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Re: KVM switch ate my display confguration

Postby Zjho » 2018-03-12 16:20

Further to bw123s comments it may be worth checking different USB connections for a USB KVM, though that seems very unlikely as USB obviously isn't directly involved in graphics.
If the KVM is temporarily taken out, does the correct resolution return ?
If it doesn't, it might also be worth checking on some basics revealed by the inxi package command :

Code: Select all
inxi -GSC

and also showing what is in /etc/apt/sources.list

Here is mine for general reference only :

deb http://deb.debian.org/debian stretch main contrib non-free

deb http://deb.debian.org/debian stretch-updates main contrib non-free

deb http://security.debian.org/ stretch/updates main contrib non-free

My KVM runs two boxes which both have onboard intel graphics and nvidia cards too.
I also abuse the KVM by putting a USB hub on the end of it for more than just keyboard and mouse, e.g. thumbdrives.
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