KDE: Keyboard lagging only in browsers (firefox+chrome)

[larienna]

I made a new thread about it because I have somewhat isolated the bug.

I have a weird issue where the keyboard is lagging and repeating characters (including control keys and arrows) but only when I am in a web page within firefox and chrome. The issue does not occur when typing in the address bar, or in any other application. This is why I am currently typing this in a text editor and copy paste it into the browser.

I really do not understand how such thing is possible. It's not an hardware or software problem, and it's not a browser specific problem.

I am currently using KDE, I don't think the issue is occuring in Mate (need to test again).

Strangely, by the time I created this post, the bug seems to be resolved. So it's active for a temporary period of time, but it occurred multiple times in the past.

Anybody have an idea?

[larienna]

I am still trying to search for a solution. Sometimes it affect other applications than browsers like for example the virtual terminal.

I found a thread with a similar issue:
https://bbs.archlinux.org/viewtopic.php?id=199346

He explains that he reverted the graphic acceleration from SNA to the old UXA, and several people reported this as the solution.

I tried to look up from some documentation on how to do this, but they always refer to using Intel graphic processor. I have an AMD processor (APU), so I don't think this is really going to solve my problem.

[blackbird]

Did you already tried with a newer kernel from the backports? If your processor and it's iGPU is new, it could have better support with newer kernels.

[larienna]

My cpu is not that recent, it's an "AMD Ryzen 5 7600 6-Core Processor". Considering the bug only happens in KDE, I did not suspect it was kernel related.

I am strongly considering installing Cinnamon.Then again, I am not sure if installing multiple Desktop environment could make them conflict with each other. When I was running Mate, it was running some KDE background process (I forgot the name). I might need to purge KDE in the process.

When I lag, the CPU is far from being overloaded and there is generally more than 24G of ram available. Since the bug occurs at random intervals, it's hard to find the cause.

[blackbird]

Since you suspected some problems with the igpu when using the browsers, I thought it could be a driver problem and a newer kernel could help. The Ryzen 7600 is from beginning 2023 and the kernel 6.1 from end of 2022 so it would be plausible that newer kernels have some improvements for the igpu.

[larienna]

Kernel version is:

Code: Select all

 $ uname -r
6.1.0-26-amd64

Could KDE access the keyboard differently than the terminal?

[blackbird]

For me this problem looks difficult to debug. Since nobody here seems to have an idea what could cause this, I would just try new versions of your software.

- Update to a newer kernel, e.g. Debian backports
- Update KDE, e.g. by installing Debian sid, Kubuntu 24.04, Fedora 40 KDE spin or trying out their live iso. These also have new kernels.
- Update UEFI

All of them could be a part of the problem you have. Since UEFI updates often can't be undone, I would try this at last.

[larienna]

I can try installing a new kernel, it could be worth it in the end. Found a guide here:

https://forums.debian.net/viewtopic.php?t=159363

Trying an ISO could be interesting. Still, I strongly think that it's one of my configuration that is creating this situation as I did not have any problems the several weeks it took me to configure my computer. Maybe it does not like putting some folder on ramdisk, or maybe it does not like my custom keyboard, I don't know.

UEFI is it no just about the booting process? How can it impact the keyboard?

[larienna]

I have installed a new kernel, and so far everything seemed to work, but you see, as I am typing this, I had a few lags, so I am not sure how long it will beeeeeeeeeeeee holding. I left the typo tthere to show you the typing results.

Code: Select all

$ uname -r
6.10.11+bpo-amd64

[larienna]

So far, I excluded any possibility of hardware issue as it appears that the bug only occurred in KDE, or was triggered by KDE. But the issue occured in plain terminal, so it could be an hardware issue. I don't have a wired keyboard available, and the symptoms seems very similar to a connection problem of a wireless keyboard.

I checked my AAA keyboard batteries with a multimeter, and they read 1.2 volt. I tried to plug in the keyboard on the front to see if there is any progress, because sometimes it have problem reaching up to the back. So far so good.

I just realized that blue tooth is available. I could try my Bluetooth keyboard, but it's also possible that Bluetooth is interfering with the keyboard communication. I could disable it and see the results.

More exploration needs to be done. I'll keep you updated.

[larienna]

So I used my blue tooth keyboard, everything worked well. I disabled blue tooth and replugged it in the back, so far, there is yet no problems. I cross my finger as I hope this was the problem. So far, everything would make sense.