I have a Xiaomi Air 12 Laptop (Intel Core m3-7Y30, Network controller: Intel Corporation Wireless 8260
(rev 3a)). I use debian Stretch (linux 4.9.0-7-amd64) with KDE and Network-Mananger (1.6.2-3).
Until now, wifi worked fine. However, after I exchanged my router (which had only 2.4 GHz) against a
newer model that has both 2.4 and 5 GHz (both frequencies with the same ssid), I experienced the
following problem: The computer switches permanently between both frequencies. This happens approximately
every 2 minutes. In /var/log/messages I find the following:
Aug 12 14:45:12 lina kernel: [ 2256.208621] wlp1s0: disconnect from AP xx:xx:xx:xx:xx:xx for new auth to yy:yy:yy:yy:yy:yy
Aug 12 14:45:12 lina kernel: [ 2256.213032] wlp1s0: authenticate with yy:yy:yy:yy:yy:yy
Aug 12 14:45:12 lina kernel: [ 2256.223163] wlp1s0: send auth to yy:yy:yy:yy:yy:yy (try 1/3)
Aug 12 14:45:12 lina NetworkManager[564]: <info> [1534077912.6843] device (wlp1s0): supplicant interface state: completed -> authenticating
Aug 12 14:45:12 lina kernel: [ 2256.228342] wlp1s0: authenticated
Aug 12 14:45:12 lina kernel: [ 2256.229481] wlp1s0: associate with yy:yy:yy:yy:yy:yy (try 1/3)
Aug 12 14:45:12 lina kernel: [ 2256.230627] wlp1s0: RX AssocResp from yy:yy:yy:yy:yy:yy (capab=0x11 status=0 aid=1)
Aug 12 14:45:12 lina kernel: [ 2256.231932] wlp1s0: associated
Aug 12 14:45:12 lina NetworkManager[564]: <info> [1534077912.6931] device (wlp1s0): supplicant interface state: authenticating -> associated
Aug 12 14:45:12 lina NetworkManager[564]: <info> [1534077912.7338] device (wlp1s0): supplicant interface state: associated -> 4-way handshake
Aug 12 14:45:12 lina NetworkManager[564]: <info> [1534077912.7414] device (wlp1s0): supplicant interface state: 4-way handshake -> completed
where xx:xx:xx:xx:xx:xx the MAC of 2.4 and yy:yy:yy:yy:yy:yy the MAC of 5 GHz net is.
However, this happens not at all places in my house. Near the router, 5 GHz is much stronger than 2.4 Ghz
and the system keeps th 5 GHz net. But in the living room, both nets have nearly the same strength and the
systems switches all the time.
I found a lot of description of exactly this problem, but no solution on the net. See e.g.
https://forum.manjaro.org/t/frequent-wifi-disconnect/12211
https://jeremyfelt.com/2017/01/02/things-i-learned-or-broke-while-trying-to-fix-my-wireless-in-ubuntu-16-10/
https://www.archybold.com/blog/post/intermittent-connectionhigh-packet-loss-intel-wireless-driver-iwlwifi-ubuntu-linux-networkmanager
I think there should be some treshold that avoids switching between nets based on small fluctiations. But
where can I set this treshold. And is the switching caused by NM or by the driver? As the bugreports
mention different adapters, I think its not driver specific.
Any hints welcome.
juergen
