[bug] Triple whammy of mt7996e bugs on 7.2+

[Ben Greear]

On 9/4/26 07:28, Ilya K wrote:
> Hey folks,
> 
> Not really sure where to report this, but I've encountered some "interesting" issues on my bpi-r4 running kernel 7.2 and up.

Hello Ilya,

In case you feel like experimenting, I'm interested to know if this kernel
works better for you.  We have some tx-hang work-arounds for mtk7996, among
other things:

https://github.com/greearb/linux-ct-7.2

We have not tested on bpi-r4 anytime recently, however, and never used WED as far
as I am aware.

Thanks,
Ben

> 
> The first issue is that after a while the firmware on the mt7996e sometimes seemingly just locks up.
> As it usually is with those things, there's not much debug info available, so all I get is
> 
> [58764.004954] mt7996e 0000:01:00.0: Message 00130022 (seq 12) timeout
> 
> This has happened before, but very rarely, and now it seems to happen consistently at least once a day or so, on
> the exact same setup that is stable for weeks on end with 7.1. I have not attempted a bisect yet because
> 1) I kinda need my network to actually work reliably and 2) it happens so inconsistently that it's hard to
> pin down a good commit.
> 
> The other issue is that the kernel then fully explodes trying to recover from this, in two different ways
> depending on whether WED is enabled or disabled: with WED on, it tries to double free a page somewhere on the
> teardown path, and with WED off it just wedges seemingly all of nl80211 and any process that happened to be talking to it.
> 
> I'm attaching the logs for both cases, hopefully this helps figure out what's going on, and happy to do more testing if
> needed.
> 
> For posterity, my current kernel tree is basically vanilla + just enough changes to get bpi-r4 10G ports working on NixOS:
> - 7.1 branch: https://github.com/K900/linux/tree/bpi-r4-71
> - 7.2 branch: https://github.com/K900/linux/tree/bpi-r4-72
> 
> (there are exactly zero *80211/mt76/mt7996e changes).
> 
> Oh, I've also tried pulling the latest firmware from vendor OpenWRT feed and that did not help matters at all.
> 
> Any help in figuring this out would be greatly appreciated!
> 
> - Ilya
> 
> 

-- 
Ben Greear <greearb at candelatech.com>
Candela Technologies Inc  http://www.candelatech.com