xorg.conf.d monitor modeline conf not being recognized

MirceaKitsune · 05-20-2022, 08:15 AM

I have a 144 Hz monitor. By default the 144 Hz option is only made available by the system when using a DisplayPort cable, but doing so comes with major issues I discussed and tried debugging in other threads. Until now I thought it's a hardware limitation of HDMI, just yesterday however I found out you can in fact get 144 Hz even on the HDMI cable. After some help and digging and fiddling I managed to get it working perfectly and at the intended pixel clocks via xrandr commands:

Code:

xrandr --newmode "1920x1080_144"  325.08  1920 1944 1976 2056  1080 1083 1088 1098 +hsync +vsync
xrandr --addmode HDMI-A-0 1920x1080_144
xrandr --output HDMI-A-0 --mode 1920x1080_144

Though it should be an easy fix, I'd rather not automate those parameters in ~/.profile but do this in a more official way. On the other side I'd rather not mess with stuff like EDID information which looks far too complex and messy. So I settled for an Xorg rule as suggested by several articles. Only problem is, it doesn't want to work for me and I'm not sure what I'm missing.

Code:

Section "Monitor"
    Identifier "HDMI"
    Modeline "1920x1080_144"  325.08  1920 1944 1976 2056  1080 1083 1088 1098 +hsync +vsync
    Option "PreferredMode" "1920x1080_144"
EndSection

I added this to a new file called /etc/X11/xorg.conf.d/50-monitor.conf (highest number used). Unfortunately nothing happens after a restart: Not only is it not using 144 Hz by default as it would on DisplayPort, the 1920x1080_144 mode isn't even listed by xrandr... I need to run commands manually to get it working again. What is my conf missing please?

Also I'm assuming this only works for an X11 session; Is there an equivalent to etc/X11/xorg.conf.d for Wayland? Or really just a better way to unlock 144 Hz on HDMI everywhere at the right specifications as the system should be doing on its own?

ferrari · 05-21-2022, 01:43 AM

Assuming an Xorg environment, a minimal xorg.conf might look something like the following...

Code:

Section "Device"
  Identifier      "Configured Video Device" 
EndSection

Section "Monitor" 
  Identifier      "Configured Monitor"
# 1920x1080 59.96 Hz (CVT 2.07M9) hsync: 67.16 kHz; pclk: 173.00 MHz
Modeline "1920x1080_60.00"  173.00  1920 2048 2248 2576  1080 1083 1088 1120 -hsync +vsync
EndSection 

Section "Screen"  
  Identifier      "Default Screen" 
  Monitor         "Configured Monitor"
  Device          "Configured Video Device" 
  SubSection "Display"
    Modes "1920x1080_60.00" 
  EndSubSection
EndSection

Replace the 'Modeline' and 'Modes' entry to match what you require. I had to use the above to make my VM guest handle the display it was connecting to several years ago as it was not getting the native resolution parsed as expected.

For Wayland, you will need to resort to the EDID approach...

https://wiki.archlinux.org/title/ker...modes_and_EDID

MirceaKitsune · 05-21-2022, 08:23 AM

Thanks, I might try that and go with it! Except I will be switching to Wayland eventually, once it finally fixes monitor power saving to be precise. If it's not insanely difficult I might just go for the custom EDID approach, but that does sound even more advance so I tried staying away from it.

Manjaro offers read-edid / get-edid so that's a good start. Unfortunately it doesn't seem to produce any useful output.

Code:

This is read-edid version 3.0.2. Prepare for some fun.
Attempting to use i2c interface
Looks like no busses have an EDID. Sorry!
Attempting to use the classical VBE interface

        Performing real mode VBE call
        Interrupt 0x10 ax=0x4f00 bx=0x0 cx=0x0
        Function unsupported
        Call failed

        VBE version 0
        VBE string at 0x0 "O�"

VBE/DDC service about to be called
        Report DDC capabilities

        Performing real mode VBE call
        Interrupt 0x10 ax=0x4f15 bx=0x0 cx=0x0
        Function unsupported
        Call failed

Reading next EDID block

VBE/DDC service about to be called
        Read EDID

        Performing real mode VBE call
        Interrupt 0x10 ax=0x4f15 bx=0x1 cx=0x0
        Function unsupported
        Call failed

The EDID data should not be trusted as the VBE call failed
Error: output block unchanged
I'm sorry nothing was successful. Maybe try some other arguments
if you played with them, or send an email to Matthew Kern <pyrophobicman@gmail.com>.

Once I generate the proper EDID with that, I understand I need to decompile it then edit it then recompile it? I don't compile a custom kernel, never did that before and it sounds complex.

Also would I need a custom kernel parameter forever? Can't the kernel at least auto-detect and load everything in the EDID directory? Especially with that it's starting to feel like a hack again.

ferrari · 05-21-2022, 04:46 PM

Quote:

Also would I need a custom kernel parameter forever? Can't the kernel at least auto-detect and load everything in the EDID directory?

In your opening post you mentioned this is a limitation when using HDMI, so yes some sort of "override" is required if you desire the 1920x180@144Hz display mode. The kernel only uses what is obtained from reading the EDID (via HDMI in your case).

What is reported by the following command?

Code:

ls -ld /sys/class/drm/card*-*/edid

This may be of interest to you...
https://github.com/akatrevorjay/edid-generator/

MirceaKitsune · 05-26-2022, 08:30 PM

Quote:

Originally Posted by ferrari

In your opening post you mentioned this is a limitation when using HDMI, so yes some sort of "override" is required if you desire the 1920x180@144Hz display mode. The kernel only uses what is obtained from reading the EDID (via HDMI in your case).

What is reported by the following command?

Code:

ls -ld /sys/class/drm/card*-*/edid

This may be of interest to you...
https://github.com/akatrevorjay/edid-generator/

Code:

-r--r--r-- 1 root root 0 May 27 04:30 /sys/class/drm/card0-DP-1/edid
-r--r--r-- 1 root root 0 May 27 04:30 /sys/class/drm/card0-DVI-D-1/edid
-r--r--r-- 1 root root 0 May 27 04:30 /sys/class/drm/card0-DVI-D-2/edid
-r--r--r-- 1 root root 0 May 26 00:08 /sys/class/drm/card0-HDMI-A-1/edid

ferrari · 05-27-2022, 05:56 AM

Here's how to install and use edid-generator to take a modeline form a file and produce a .bin file...

https://kodi.wiki/view/Archive:Creat...d-generator.29

Once you have a suitable custom EDID (saved to /usr/lib/firmware) to suit the desired mode, follow the instructions in the ArchWiki page I linked to already.