Date: Mon, 27 May 2024 16:31:08 -0700 From: Adrian Chadd <adrian.chadd@gmail.com> To: "Bjoern A. Zeeb" <bz@freebsd.org> Cc: FreeBSD wireless mailing list <wireless@freebsd.org> Subject: Re: wireless porject status report Message-ID: <CAJ-Vmok%2B6KuwOrPkTzViadVrdhQBSBomGOem_D13PcqFjbdrRw@mail.gmail.com> In-Reply-To: <4rq46736-pnp2-nrp2-r3q9-3r3s3256os84@SerrOFQ.bet>
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[-- Attachment #1 --] On Mon, 27 May 2024 at 15:59, Bjoern A. Zeeb <bz@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) and see what happens. A lot of this stuff originally used flags in multiple threads without actually using atomics + barriers and it was just super easy to get stuck :( -adrian [-- Attachment #2 --] <div dir="ltr"><div dir="ltr"><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, 27 May 2024 at 15:59, Bjoern A. Zeeb <<a href="mailto:bz@freebsd.org">bz@freebsd.org</a>> wrote:</div><div dir="ltr" class="gmail_attr"><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> Last I got fed up by SCAN problems this afternoon and started<br> investigating. Have other people (with iwn/iwm/iwlwifi or others) noticed<br> the fact that once you are associated with a channel in a band (say Channel<br> 6) you will not get scan results for 11a/5Ghz anymore? Or that<br> sometimes scanning will "just stop" (way beyond scanvalid interval) and<br> triggering a manual scan (or from wpa_cli) you either just get the old cache<br> or EINPROGRESS? (checking ddb on-off I noticed that the scan got stuck<br> in ACTIVE or BGSCAN was on suddenly despite IEEE80211_FEXT_SCAN_OFFLOAD<br> is set given iwlwifi does hw_scan and we never enable background<br> scanning).<br> I know this has bugged me in the past a lot on iwm(4) on 8xxx chipsets<br> and ifconfig down/ifconifg mode auto/ifconfig up fixed it again.<br> In case more people have observed similar things, please let me know<br> so we can properly track this.<br></blockquote><div><br></div><div>Oh, wow, this is still a problem? Aiee. I remember fixing a WHOLE lot of races</div><div>in the non scan offload and the then-new scan full offload paths.</div><div><br>I'll see if I can reproduce it on iwn(4) (which supports full scan offload) and</div><div>see what happens. A lot of this stuff originally used flags in multiple threads without</div><div>actually using atomics + barriers and it was just super easy to get stuck :(</div><div><br></div><div><br></div><div><br></div><div>-adrian</div><div><br></div></div></div>home | help
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