Bug 240776 - iwm: Can't find wifi networks after short time since network restart
Summary: iwm: Can't find wifi networks after short time since network restart
Status: Open
Alias: None
Product: Base System
Classification: Unclassified
Component: wireless (show other bugs)
Version: CURRENT
Hardware: amd64 Any
: --- Affects Only Me
Assignee: freebsd-wireless (Nobody)
Keywords: needs-qa
Depends on:
Reported: 2019-09-23 16:28 UTC by Johannes Lundberg
Modified: 2019-11-27 18:08 UTC (History)
4 users (show)

See Also:
koobs: mfc-stable12?
koobs: mfc-stable11?


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Description Johannes Lundberg freebsd_committer 2019-09-23 16:28:15 UTC
This has been a long existing problem for on my Dell laptops. Always running recent 13-CURRENT and the hardware is

iwm0@pci0:2:0:0:	class=0x028000 card=0x00508086 chip=0x24fd8086 rev=0x78 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = 'Wireless 8265 / 8275'
    class      = network

The other Dell laptop has the previous generation of this chip.

After using the laptop "normally" (wired or wireless) for a while, it stops finding networks on scan with the result that roaming almost never works (it doesn't find other networks as I move between work-home). I've tested this with and without lagg failover configured.

As soon as I do 'service netif restart' it can again see all networks with 'ifconfig wlan0 scan'. For a while that is. After a short time (sub-hour to hours), scan will show either only a subset of networks or none at all and the only remedy is to tear down the interfaces and configure them again.
Comment 1 Kubilay Kocak freebsd_committer freebsd_triage 2019-09-24 01:42:24 UTC

Could you include:

- Exact FreeBSD version (uname -a)

And as attachments:

- /var/run/dmesg.boot output
- pciconf -lv output 
- ifconfig -a output on the wlan interface (once associated)
- Any potentially relevant /var/log/messages (or console.log) messages
- Enable net.wlan.debug sysctl , any relevant output

You may also want to try (if relevant):

- wpa_supplicant(8) -d = increase debugging verbosity
- wlandebug(8)

See Also:

- base r324434 - Add support for Intel 8265 WiFi (committer cc'd)
- https://lists.freebsd.org/pipermail/freebsd-questions/2017-July/278103.html

I also note that man iwm only shows (explicit) support for:

          Intel Dual Band Wireless AC 8260

If 8265 / 8275 are explicitly supported, it may be worth adding these to the man page