On Wed, Mar 16, 2022 at 07:56:20AM -0500, [email protected] wrote: > On Wed, Mar 16, 2022 at 10:11:50AM +0100, Stefan Sperling wrote: > >Looks like a firwmare or driver issue to me. > > > >Sorry, without having a reproducible test case in front of me, there > >is nothing I could do fix this from afar. > > I mean, in fact it's 100% reproducible. > > >You could try moving the AP to a different channel as a workaround. > > I've already tried that and it doesn't solve the problem at all. > > Thanks anyway.
APs not showing up in the 5GHz band has always been a problem on Intel cards. It goes back to older drivers like iwn(4) or perhaps even ipw(4). In all cases I know of so far, repeating the scan made the AP appear eventually. This is the first time I know of where it never appears. There is some firmware-specific behaviour involved that is mostly beyond the driver's control, and even the little of what the driver can do mostly eludes my understanding and is not well documented. Because upper ranges of the 5GHz band are restricted, the Intel firmware does not allow the driver to simply send a frame without having done some internal checks first. I don't know how this really works. It might involve listening on the channel for some time to see if a valid 802.11 frame is received before sending anything on a channel. While scanning channels the firmware does not have a lot of time to listen on each of them all. Effectively this also means that all scans on 5GHz are passive, i.e. the firmware will not send a probe request, it will only listen for a beacon, which could be missed based on timing. Scans on 2GHz are more reliable for this reason. We run the firmware in the "world" regulatory domain. The Linux driver will adapt the regdomain using various heuristics and perhaps open up some channels in the 5GHz band which firmware is gating by default. So perhaps that would help you. However it is a lot of work to add this feature. Simply using the world domain is easy and has never really been an issue. None of this answers the question of why you are seeing 30% packet loss on 2GHz, though. Is there really that much traffic on channel 1-11? If other devices work, perhaps there is something wrong with your hardware or antenna setup? I don't know what to suggest, just again pointing out that there are configurations similar to yours that are known to work :-/ If you get a chance to try the device in a different RF environment to see if it works there, that might already tell you something.
