Subject: Re: iwlwifi warnings in 5.5-rc1

From: Toke Høiland-Jørgensen <[email-masked]>
Date: Wed, 11 Dec 2019 09:53:10 +0100

Johannes Berg <[email-masked]> writes:

> On Tue, 2019-12-10 at 13:46 -0700, Jens Axboe wrote:
>> Hi,
>> 
>> Since the GRO issue got fixed, iwlwifi has worked fine for me.
>> However, on every boot, I get some warnings:
>> 
>> ------------[ cut here ]------------
>> STA b4:75:0e:99:1f:e0 AC 2 txq pending airtime underflow: 4294967088, 208
>
> Yeah, we've seen a few reports of this.

FWIW I've tried reproducing but I don't get the error with the 8265 /
8275 chip in my laptop. I've thought about sending a patch for mac80211
to just clear the tx_time_est field after calling
ieee80211_sta_update_pending_airtime() - that should prevent any errors
from double-reporting of skbs (which is what I'm guessing is going on
here). However, it kinda feels like a band-aid so I'd much rather figure
out why this particular driver/device combo cause this :)

> I guess I kinda feel responsible for this since I merged the AQL work,
> I'll take a look as soon as I can.

Sounds good, thanks!

-Toke