Thorsten Leemhuis <regressi...@leemhuis.info> writes: > Hi, this is your Linux kernel regression tracker speaking. > > On 27.11.21 13:21, Nuno Oliveira wrote: >> * Sebastian Bachmann <he...@reox.at> [2021-11-27 08:17]: >> >>> I recently upgraded my Debian based AP from buster to bullseye, just >>> to find out that hostapd does not work any more, because all 5GHz >>> channels are marked as No-IR. This regression was already discussed on >>> this ML here: >>> https://www.mail-archive.com/ath10k@lists.infradead.org/msg12018.html >>> and there is also an entry in Debian's bug tracker for the same issue: >>> https://bugs.debian.org/959821 >>> >>> I have a slightly different card (branded Compex WLE200NX): >>> 04:00.0 Network controller: Qualcomm Atheros AR928X Wireless Network >>> Adapter (PCI-Express) (rev 01) >>> Subsystem: Qualcomm Atheros AR928X Wireless Network Adapter >>> (PCI-Express) >>> Kernel driver in use: ath9k >>> Kernel modules: ath9k >>> >>> But as you can see, also the EEPROM gets sanitized: >>> [ 15.461755] ath9k 0000:04:00.0: enabling device (0000 -> 0002) >>> [ 15.911600] ath: EEPROM regdomain sanitized >>> [ 15.911612] ath: EEPROM regdomain: 0x64 >>> [ 15.911615] ath: EEPROM indicates we should expect a direct regpair >>> map >>> [ 15.911625] ath: Country alpha2 being used: 00 >>> [ 15.911628] ath: Regpair used: 0x64 >>> >>> I read in the other thread, that this is a regression, but the actual >>> commit causing it was never reverted. >>> I tried to search for newer messages explaining the issue, however as >>> far as I can tell, the thread ends in June 2020 with no solution >>> available. >>> >>> Therefore, I kindly want to ask if there is any workaround available >>> to re-enable 5GHz channels in AP mode for my card? (expect sticking to >>> a pre-5.6 kernel or manually patching and recompiling ath) >> >> After June 2020 there were other users also affected by this change (see >> e.g., >> https://lists.infradead.org/pipermail/ath10k/2021-August/012802.html). >> Users were complaining that this change was too restrictive since it >> meant that the intersection of restrictions for regdomains 0x00, 0x64, >> US, and their local domain, together with a cumulative mode of applying >> these constraints meant that, in practice, they would not be able to use >> their world domain cards anymore as APs in the 5GHz band, for certain >> regdomains where they were located. >> >> And several people pinpointed the exact source changes responsible for >> this. In my case, I ended up applying the attached patch, that just >> loads the parameters for the regdomain that I'm interested in >> (CTRY_PORTUGAL). I'm not in the US; and I care for their regulatory >> restrictions as much as they are interested in mine. >> >> So I think that you might be able to use the attached changes, with the >> specific CTRY_xxx parameter suitable for your case. And then recompile >> the respective Debian kernel package, which takes a lot of CPU if you >> just recompile the whole package. Let me know if you need instructions. >> >> A more robust option would be to go the OpenWRT way, and use their >> patches to make this country selection a parameter for the kernel >> module. This way, you would just reload the kernel module to change to a >> new regdomain, subject to the restrictions of your hardware / firmware. >> I have not looked into that. Please let me know if you isolate these >> patches. >> >> In any case it seems difficult to escape a kernel recompile, due to this >> small, entirely legitimate, yet remarkable decision by the driver >> maintainers. > > This is a regression due to 2dc016599cfa ("ath: add support for special > 0x0 regulatory domain") that seems to affect quite a few users, but > afaics was never properly addressed. I fully understand that this might > be a special case where Linus' "no regressions" rule can't be simply > applied.
Yes, this is a tricky problem and I am taking a second look at this. Regulatory rules are complicated and we do not want to break them in any circumstance. I see two ways to workaround this: 1) calibrate your board with a correct country code (which is impossible for an average user) 2) use 2.4 GHz band > But isn't there some way to provide users with a solution that doesn't > force users to compile a module or a kernel? Like a module-parameter > that only works if the the regulatory domain code in the EEPROM is empty > (as apparently used by OpenWRT?). Yes, module parameters are normally a > bad idea, but this case it might be a situation where it's the best > solution. I don't think setting the country code via a module parameter would be acceptable for the authorities, more info here: https://wireless.wiki.kernel.org/en/developers/regulatory -- https://patchwork.kernel.org/project/linux-wireless/list/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches _______________________________________________ ath10k mailing list ath10k@lists.infradead.org http://lists.infradead.org/mailman/listinfo/ath10k
