1

Hello,

I have been using CachyOS for quite a while now, and up until a month or so ago it has been a completely smooth experience.

Unfortunately something seems to have regressed in regards to the Wi-Fi driver my system has, which is a MT7921K (RZ608). Whenever I’m playing a game that requires low latency I have very, very noticeable ping spikes, jumping upwards to 2000ms for a couple seconds before settling back down to my normal values.

This has rendered certain games completely unplayable as every 3 minutes or so there’s a chance I’m rendered completely vulnerable.

As for the steps I have tried to resolve this:

The arch wiki makes note of these drivers as having high latency problems, which is what I experience, so I’ve tried to apply their fix, however after rebooting, aspm does mention it’s disabled, but the latency spikes continue anyway.

❯ cat /etc/modprobe.d/wifi.conf
options mt7921e disable_aspm=1

29:00.0 Network controller: MEDIATEK Corp. MT7921K (RZ608) Wi-Fi 6E 80MHz
        DeviceName: RTL8111E Giga LAN
        Subsystem: MEDIATEK Corp. MT7921K (RZ608) Wi-Fi 6E 80MHz

... ...
                        ASPM Disabled; RCB 64 bytes, LnkDisable- CommClk+

I’ve tried this random GitHub fix GitHub - smoliicek/mt7921-fix: Fix for the MT7921 WiFi card using the mt7921e driver on Linux. · GitHub, which doesn’t seem to have helped either.

The only other mention of this problem I can find in this forum is this thread, but the resolution of “I bought a different device” isn’t particularly helpful to me.

I’ve confirmed this issue is not a internet problem as when I swap to my Windows partition the problem goes away entirely.

I’m not entirely sure what to do from this point, but I cannot keep ignoring the issue as it’s become increasingly annoying to try and tolerate, I simply cannot play games like this.

  1. Roughly how many days ago did you start experiencing problems? Could you give an estimate
  2. Do you experience any noteworthy lag spikes during browser or other general application usage?

In case of a recent breakage (like 3 weeks ago or something), consider rolling back your system with snapper

1. List available snapshots

sudo snapper list -t pre-post

2. (Optional) get a list of changed files from a snaptshot (e.g sudo snapper status 140..230):

sudo snapper status PRE..POST

# Then undo those changes using:

sudo snapper -v undochange PRE..POST

After rolling back you could do some shenanigans with pinning the wifi driver package (so it doesn’t update) but I don’t have experience with those commands so you’d have to research that yourself. You have to also be cautious with stuff like this to not pin something that other packages depend upon.

So find which wifi package change is the culprit, and if successful, you can full system upgrade again to the most recent packages.

At least you know that your WIFI driver used to work normal. This means that any point-release distro that was created before your issue probably still works for your device. It would be a last resort of-course but Arch-based distros aren’t the easiest to get/keep working for everyone, so I wouldn’t say it’s a bad decision. Not saying that you could still make CachyOS work for you, just saying it’s not easy in your particular setup.