Black screen amdgpu error: no EDID read

nothing changed :cry:

How do set the displayport version to 1.1?

Some where in System SetupDisplayPort Version
But can you try using grub instead of systemd? (newbie) Unable to change the screen resoultion using xrandr - #7 by axolotlKing
just change this in your config:

#delete that
  boot.loader.systemd-boot.enable = true;
  boot.loader.efi.canTouchEfiVariables = true;

#add this:
  boot = {# Bootloader
    loader = {
      efi.canTouchEfiVariables = true;
      grub ={
        enable = true;
        device = "nodev";
        efiSupport = true;
        useOSProber = true;
      };
    };
  };

nothing changed from the new boot loader.

the newbie link did have something that looks interesting. a link in the edid for nix options mentions my exact monitor

well looking at it again. nothing changed b/c Failed to install bootloader :confused:

I got it to load grub

What do you mean by

Did it work with grub?

grub loaded, but the screen is still black

I’ve been combing through the manual. It mentions my exact monitor.
https://nixos.org/manual/nixos/stable/#module-hardware-display-edid-linuxhw

PG278Q is the example monitor. Even with the example in the manual, nothing changes and the monitor is black. I’ll try going through kernel versions in case an older version works.

Yeah you can try that. But also try out different cables and try the monitor on a different device. With trying the monitor an a different device we can rule out a monitor defect. Also for that use the same cable and than try using another cable.
Also could you try using the monitor with hdmi?

The monitor works. On bootup, pg278q is the default and I select the nix build to boot from. The pc was windows11 and worked with it.

I did look to try different ports. I only have a dp connetor on the pg278q. Without a dp to hdmi dongle, I can not try it on that monior.

But I did connect the other monitor to a dp and got the black screen. Looks like non of my video card dp connectors have output.

Than I don`t think it is a EDID issue.
Can you post your journalctl log and dmesg log on pastbin.com and share the link

dmesg

journalctl

So the logs seem fine.
What I was able to find was that grub does not need the EDID to display something.
Could you try this:

  hardware.display.edid.packages = [
    (pkgs.runCommand "edid-custom" {} ''
       mkdir -p $out/lib/firmware/edid
       base64 -d > "$out/lib/firmware/edid/custom1.bin" <<'EOF'
       <AP///////wAEabEnQ80AACYYAQSlPCJ4BkzhpVhQoCMLUFQAAAABAQEBAQEBAQEBAQEBAQEBVl4AoKCgKVAwIDUAVlAhAAAaAAAA/wAjQVNOOGxhbVJWZVhkAAAA/QAelh7SNgEKICAgICAgAAAA/ABST0cgUEcyNzhRCiAgAcUCAwoBZUsEAAEBWocAoKCgO1AwIDUAVlAhAAAaWqAAoKCgRlAwIDUAVlAhAAAab8IAoKCgVVAwIDUAVlAhAAAadNIAFqCgCVAEEBEAVlAhAAAeHCUAoKCgEVAwIDUAVlAhAAAaAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAArw==% `base64 < /sys/class/drm/card0-.../edid`>
       EOF
    '')
  ];
  hardware.display.outputs."DP-2".edid = "custom1.bin"; //should replace the bootparamenters

For this comment the bootparams out.

https://nixos.org/manual/nixos/stable/#module-hardware-display-edid-custom

error: builder for '/nix/store/6440w645w1paf8qmajfqvlkq0gdm06b1-edid-custom.drv' failed with exit code 1
error: 1 dependencies of derivation '/nix/store/k1m2vvqjgz1lqb841svymglz7mxppwfg-firmware-edid.drv' failed to build
error: 1 dependencies of derivation '/nix/store/0fni556vxrbhakrhaj2sx79svazavsv1-firmware.drv' failed to build
error: 1 dependencies of derivation '/nix/store/sw679j30nj7af6d6wblckjqq4hiw0225-nixos-system-nixos-24.11.717703.5b35d248e920.drv' failed to build

Ok we could try a different approach:

hardware.display.edid.enable = true;
hardware.display.edid.linuxhw = {
  PG278Q_2014 = [ "PG278Q" "2014" ];
};
hardware.display.outputs = {
  edid.modelines."PG278Q_60" = "241.50   2560 2608 2640 2720   1440 1443 1448 1481   -hsync +vsync";
//or for 120HZ:
  edid.modelines."PG278Q_120" = "   497.75   2560 2608 2640 2720   1440 1443 1448 1525   +hsync -vsync";

  outputs."DP-2".edid = "PG278Q_60.bin"; // if you use the 120HZ option change "PG278Q_60.bin" to "PG278Q_120.bin"
  outputs."DP-2".mode = "e";
}

Also can you make sure that the monitor works with the card on other OS like windows. That way we can rule out possible hardware issues. Also pleas try it with a different cable.

I have tried all the stuff in the manual. linuxhw, modelines, complete example

The monitor and cable work. They worked at boot, when this pc had windows11, on the previous pc with nix, just not this pc with nix. I have tried other DP cables but none of the DP connectors have an output, only the 1 HDMI has output.

i’ll give ubuntu a try and see what happens.