Random Wifi disconnects on Kernel 5.3.0-76

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IBM1130
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Iscritto: 09/24/2020

After a recent update, my Libreboot Thinkpad began experiencing random freezes. At the kind suggestion of Magic Banana, I upgraded to Kernel 5.3.0-76. This completely solved the freezing problem. However, the upgrade resurrected a wifi problem which an update to the old Kernel had fixed several months ago.

The problem: my wifi randomly drops and refuses to reconnect. The wifi also temporarily loses my credentials and continually asks for my password. But entering the password does no good. The router is fine and other computers on my network are unaffected. My Thinkpad runs an Ath9k card which uses the open source driver in the kernel.

When the wifi disconnects, re-connection is impossible for a random length of time. DMESG gives the following repetitive output:
[392782.484040] wlp2s0: authenticate with [router]
[392782.507401] wlp2s0: send auth to [router] (try 1/3)
[392782.568930] wlp2s0: send auth to [router] (try 2/3)
[392782.625661] wlp2s0: send auth to [router] (try 3/3)
[392782.681152] wlp2s0: authentication with [router] timed out

After many months of unsuccessful troubleshooting with the old Kernel, the issue suddenly cured itself in May or June. I suspect that a fix was included in an update to the Ath9k driver, systemd or the kernel's crypto functions.

Does anyone have a changelog of Trisquel updates from May-June 2021? This may help me understand the problem.

Any other suggestions would be welcome.

Thanks!

amenex
Online
Iscritto: 01/04/2015

With two wifi modules, both supplied by ThinkPenguin, one postage-stamp-sized,
the other an extended-range model, I have a simple solution at similar occurrences
to IBM1130's: I switch to the other USB-connected module. Switching them hot can
freeze the computer, so the safe way is to shut down, switch wifi devices on the
USB bus, and reboot, whereupon everything is copacetic again.

IBM1130
Offline
Iscritto: 09/24/2020

Thanks Amenex. I have a small update on my wifi situation. Random disconnects are still occurring with frustrating regularity. However, I discovered that I can often reconnect by running the following commands:

sudo modprobe -v ath9k
sudo service network-manager restart

This seems to work, but is annoying.

I have also discovered that my Ath9285 wifi card apparently does not play well with "mixed mode" on my router. When I changed the router setting from Mixed to NG-Mixed, speed increased and the connection now authorizes & associates almost instantly --- at least when my wireless bug is not occurring. By contrast, using Mixed mode causes the authorization & association process to proceed slowly and time-out numerous times. Please note that I have several other Linux laptops running Mint, Lubuntu, etc. on the network. Only Trisquel with ath9k was having this issue with Mixed mode.

As a workaround to my wifi disconnects, I just bought an old 802.11g PCMCIA card. (Yes, my old laptop still has a PCMCIA slot!) The card uses a different driver and may help narrow down the bug. We'll see.