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jamincollins

Member

Registered: 2019-03-08

Posts: 4

[solved] override monitor settings

I need to override the detected modes for my monitor.

By default X attempts to set the monitor to 2560x1440 with a refresh rate of 120.

$ xrandr
...
HDMI-0 connected 2560x1440+0+0 (normal left inverted right x axis y axis) 698mm x 392mm
   2560x1440    120.00 + 143.93    59.95* 

However, I have the display running through a KVM that does not support a refresh rate higher than 60.  With any higher refresh rate the monitor continuously resets (disconnects and reconnects in the X.org log).

I've tried creating an xorg.conf.d file with the following:

Section "Monitor"
    # HorizSync source: edid, VertRefresh source: edid
    Identifier     "HDMI-0"
# 2560x1440 (0x2ab) 241.500MHz +HSync -VSync *current
#       h: width  2560 start 2608 end 2640 total 2720 skew    0 clock  88.79KHz
#       v: height 1440 start 1443 end 1448 total 1481           clock  59.95Hz
    Modeline    "2560x1440_60"  241.5  2560 2608 2640 2720  1440 1443 1448 1481 +hsync -vsync
    Option      "PreferredMode"	"2560x1440_60"
EndSection

However, this does not seem to be used at all.

Last edited by jamincollins (2023-05-30 14:29:23)

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 25,285

Re: [solved] override monitor settings

What are you using inside/on X? If a desktop environment they are certainly overriding this with their own tooling and you'd want to make the adjustment there

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 76,734

Re: [solved] override monitor settings

On top of that, iff this is on nvidia, it ignores the PreferredMode, you'll have to add a Screen section with a desired metamode config (you can use nvidia-settings to generate that, don't write the xorg config, just preview it and copypaste the relevant part)

Otherwise and in doubt please post your xorg log.

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jamincollins

Member

Registered: 2019-03-08

Posts: 4

Re: [solved] override monitor settings

What are you using inside/on X? If a desktop environment they are certainly overriding this with their own tooling and you'd want to make the adjustment there

LightDM and XFCE

I was testing my changes by restarting LightDM, but it appears that was insufficient, perhaps the x.org.conf.d snippets aren't fully parsed when restarting just LightDM.  A full reboot and the above seems to be working.