Acer XB280HK 4k monitor stuck in 640x480

Hi, new to linux.

I just installed Bazzite(fedora based) on my computer(Ryzen 5800x3d & 9070XT) and it went well except for the fact that my 4k monitor is stuck at 640x480 (Acer XB280HK). There is not even a drop down option in the menu for other resolutions.

After some googling it appears to be a problem with the EDID file for this monitor. Apparently because this is an early gsync monitor this is a common issue.

I have been unable to find a comprehensive step-by-step guide on how to fix this, so I’ve been using Gemini to guide me. It actually seems to know what it’s doing with the exception of one step:

when it has me download the EDID file from github the link 404’s so there isn’t actually a file being downloaded to fix the issue. Once i tell it this it tries to build a new EDID from scratch but this never works.

There is people online that have used a “Modeline” to modify the original EDID file but I have no idea what this means or how to do this and Gemini says I can’t do it in Bazzite due to fedora being atomic(?).

I will include links to all the information I have and will answer any questions asked, thanks

The two fix threads i’ve found online but have no idea how to use this information:

The github link Gemini is trying to use to download a new EDID .bin file:

Thank you for any help

I will be on a totally fresh Bazzite install FYI

I should add that the process that Gemini was trying to accomplish was downloading an EDID, placing it in the right place, “packing” it for the OS, then directing the OS to use it. Roughly. Again I’m new to Linux this is all foreign to me.

Did you see this link?

Gemini is correct that Bazzite is atomic, but there are workarounds for that issue. Someone using an atomic system may be able to help there.

The link from github you posted does not work. I backed up all the way to the base url for that user and the following parts do not even exist on that site. I could find none of his repos that contain anything about acer nor edid (though I did not do an exhaustive search)

I did find these 2 suggested modeline entries.
Modeline "3840x2160_24" 209.760 3840 3888 3920 4000 2160 2163 2168 2185 +hsync -vsync
and
modeline: "3840x2160_60" 533.250 3840 3888 3920 4000 2160 2163 2168 2222 +hsync -vsync

I also found it suggested that you place those entries in your ~/.profile or ~/.bash_profile file and it should then work when you log in.

It seems that monitor has had problems for years and is a poor choice to use.

I have a 65" LG TV (4k) that I use as a monitor on hdmi and have never had an issue with it.

I think modeline is an xorg.conf thing, not something for the bash profile. (Those lines would just error if placed in the bash profile, unless there’s something that provides a command called Modeline.)

I don’t know how this translates across to Wayland.

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The poster here has an approach that worked for them on Wayland, by creating a modified EDID file and referencing it in the kernel boot parameter drm.edid_firmware:

It does involve writing to /lib/firmware though, which won’t be possible on an atomic system - not sure if there is a workaround for that.

Is this something I can fix by connecting the monitor to a windows computer? Maybe extracting the EDID .bin in windows then using that file in Bazzite?

Isn’t the problem that the monitor’s EDID is incorrect, so you have to create a correct one rather than just extract what the monitor provides?

I might be misunderstanding though.

I really don’t know, this stuff is foreign to me. Willing to run any necessary commands to fully troubleshoot the specific issue

Yes I see that link but the link inside of it is dead and therefore is of no help.

I don’t know what to do with those Modeline entries or where the files they’re supposed to go in are located or anything. Total noob here.

SOLVED: I did eventually get Gemini to find a solution for me that worked, but it took over 200 prompt entries and almost an entire week of fighting it to get it to work. After the fact, I made it give me a summary of what worked and coalesced it in to a series of commands that it THINKS should work, although it gave me tons of commands that DIDN’T work to get to this point so YMMV.

I will post it’s attempt at a summary of what worked, and will also post the entire chat log so if you want to go through the entire thing or have AI do that for you you can do that. In the full chat log if you search “worked” you will find the parts where I say the solutions worked and you can look at what was directly above that to see what was entered. I had two phases of success, one where the resolution finally switched to the correct resolution, and one where we got it do do that at boot, fighting through issues that forced the computer into emergency mode when trying to bake it into the boot cycle.

Here is the link to the full chat log: https://drive.google.com/file/d/1svKfXXP6wYZi9FF1eOi0UEuX3sqBTo84/view?usp=sharing

Here is Gemini’s solution:

 

 

 

To recreate our successful result on a clean Bazzite installation—achieving that perfect 3840x2160@60Hz output on DP-3 while avoiding the “Emergency Mode” trap—you would follow this specific, streamlined sequence.

This approach respects Bazzite’s atomic nature and KDE/Wayland’s specific way of handling displays.

Phase 1: The Bandwidth & Stability Fix

Before forcing resolutions, we must ensure the AMD driver is allowing the necessary bandwidth and stability for a 4K/60Hz signal. This is the “under the hood” fix that prevents flickering or signal dropouts.

Run this in your terminal:

sudo rpm-ostree kargs --append="amdgpu.dcfeaturemask=0x2" --append="bluetooth.disable_ertm=1"
  • What this does: The dcfeaturemask helps resolve bandwidth/sync issues on certain AMD cards, while the bluetooth flag is a standard Bazzite optimization for controller stability.

Phase 2: The Wayland Resolution “Force”

Since Bazzite uses KDE Plasma on Wayland, the most reliable way to force a resolution without breaking the bootloader is using kscreen-doctor. This tool talks directly to the Wayland compositor.

Enter this to test the resolution immediately:

kscreen-doctor output.DP-3.mode.3840x2160@60
  • Verification: If your screen blinks and returns at the correct 4K resolution, the hardware handshake is successful.

Phase 3: The “Zero-Risk” Automation

Instead of messing with the kernel arguments (which caused our emergency mode failure), we create a lightweight startup script. This ensures the resolution is applied the moment you log in, staying completely clear of the bootloader’s sensitive files.

  1. Create the script directory:

    mkdir -p ~/.config/autostart-scripts
    
  2. Create and edit the script:

    nano ~/.config/autostart-scripts/set-resolution.sh
    
  3. Paste this exact content:

    #!/bin/bash
    # Wait 2 seconds to ensure the Wayland compositor is ready
    sleep 2
    kscreen-doctor output.DP-3.mode.3840x2160@60
    
  4. Make it executable:

    chmod +x ~/.config/autostart-scripts/set-resolution.sh
    
  5. Tell KDE to run it at login:

    • Open System Settings.
    • Go to Startup and Shutdown > Autostart.
    • Click + Add > Add Login Script.
    • Select the set-resolution.sh file you just created.

Why this is the “Golden” Re-creation:

  • Safety: By using kscreen-doctor instead of kernel arguments (video=...), you are 100% immune to Emergency Mode. Even if the script fails, the system will still boot to a desktop.
  • Atomic Friendliness: It doesn’t require “pinning” or modifying read-only system files.
  • Clean Syntax: It avoids the “split-line” error in ostree-1.conf that caused our biggest headache.
  • Bandwidth Aware: It keeps the amdgpu.dcfeaturemask, which ensures the hardware actually has the “pipe” width to push 4K pixels.

Final Step: Simply systemctl reboot. You should see the Bazzite logo, followed by a seamless transition into a perfectly scaled 4K desktop.

Does that clean-slate plan align with the “perfect” version of the journey you were looking for?