Re: iwm: loosing connection to AP very often

From: Bjoern A. Zeeb <>
Date: Fri, 24 Sep 2021 10:59:02 UTC
On Sun, 12 Sep 2021, wrote:


> I observe a very negative and unpleasant development and behaviour with Intel iwm driver
> in FreeBSD recently. Using this WiFi adapter in a Lenovo E540 (technical specs see below,
> output of pciconf -lvbc), this adapter ran stable with FreeBSD 12-CURRENT some time ago,
> until I moved to 13-STABLE on that notebook.
> I use a "typical" wlan0/re0/lagg0 configuration on that notebook, since I have to switch
> very often between WiFi and wired LAN. The FreeBSD 13-STABLE (most recent incarnation) is
> configured dual stack IPv4 and IPv6.
> The overall observation is that the WiFi connection is, no matter what kind of AP I used
> to be connected to, that the connection is highly unstable! While ifconfig still reports
> attached IPs (both IPv4 and IPv6) on lagg0 and allegedly beeing associated via wlan0 to
> the AP, there is no connection any more and the only salvation is service netif restart
> or bringin down and up IF and all associated services. This problem gets worse, the more
> the WiFi is crowded with other stations, but even in sparsely populated WiFi areas the
> loose of connection/association is only a matter of time, sometimes the death of the
> connection comes rather quickly.
> I can only report my observations. I used to use the very same notebook with FreeBSD
> CURRENT and lately with 13-STABLE with FreeBSD since I purchased it in 2014 and used the
> same wlan0/re0/lagg0 configuration I use these days, but with I never faced an
> instability like the reported with 12-STABLE I face with 13-STABLE. The problem is
> present almost 1 1/2 years for now and even with newer commits to WiFi in FreeBSD I did
> not see a mitigation.

Without much more data this is hard to diagnose remotely.  I'd suggest
(if you are okay with the extra logging) to enable wlandebug such as:
 	wlandebug_wlan0="+state +crypto +node +auth +assoc +dot1xsm +wpa"
in rc.conf.  See wlandebug(8) for more information.  That might give
you a hint maybe of what is going wrong.

> I also realized that iwm() is limited by its FreeBSD driver to 802.11b and 802.11g,

and 11a.

> although it claims to be an 802.11ac driver. Is this about to change in a measurable
> timeframe for a human lifetime?

That is underway with the iwlwifi efforts.  See the posting with the
reference to the wiki earlier this month on this list:

Fair warnings:
It's probably not quite fully ready/stable enough for your roaming
usage but if you are willing to test you are more than welcome.
I am also not aware anyone having tested iwlwifi with a 7000 series card
yet and I don't happen to have one either to do so.  Could be an extra
bumpy ride.

> [...]
> iwm0@pci0:5:0:0:        class=0x028000 rev=0x73 hdr=0x00 vendor=0x8086 device=0x08b2
> subvendor=0x8086 subdevice=0x4262 vendor     = 'Intel Corporation'
>    device     = 'Wireless 7260'

From what I can see this is a very early 11n-only device so 11ac won't
help with it; but 11n would hopefully help you a bit.

Bjoern A. Zeeb                                                     r15:7