On Mon, 27 May 2024, Adrian Chadd wrote:
On Mon, 27 May 2024 at 15:59, Bjoern A. Zeeb <b...@freebsd.org> wrote:
Last I got fed up by SCAN problems this afternoon and started
investigating. Have other people (with iwn/iwm/iwlwifi or others) noticed
the fact that once you are associated with a channel in a band (say Channel
6) you will not get scan results for 11a/5Ghz anymore? Or that
sometimes scanning will "just stop" (way beyond scanvalid interval) and
triggering a manual scan (or from wpa_cli) you either just get the old
cache
or EINPROGRESS? (checking ddb on-off I noticed that the scan got stuck
in ACTIVE or BGSCAN was on suddenly despite IEEE80211_FEXT_SCAN_OFFLOAD
is set given iwlwifi does hw_scan and we never enable background
scanning).
I know this has bugged me in the past a lot on iwm(4) on 8xxx chipsets
and ifconfig down/ifconifg mode auto/ifconfig up fixed it again.
In case more people have observed similar things, please let me know
so we can properly track this.
Oh, wow, this is still a problem? Aiee. I remember fixing a WHOLE lot of
races
in the non scan offload and the then-new scan full offload paths.
I'll see if I can reproduce it on iwn(4) (which supports full scan offload)
You should know better given you introduced this ..
Reproducing on iwn(4) will be hard unless you change the driver... supports
(in theory) and "supports" (is implemented and working) .... just saying ...
% grep -r IEEE80211_FEXT_SCAN_OFFLOAD sys/dev/
sys/dev/iwm/if_iwm.c: ic->ic_flags_ext = IEEE80211_FEXT_SCAN_OFFLOAD;
sys/dev/usb/wlan/if_rsu.c: ic->ic_flags_ext |= IEEE80211_FEXT_SCAN_OFFLOAD;
It's a hacked up solution and scrolling through I found at least two
places where the logic seems wrong (and it's only what--8 checks in
total?). I think atomics are the least of my concerns here...
--
Bjoern A. Zeeb r15:7
