Hi On Sunday 10 April 2011, Anton Ivanov wrote: > On 04/10/11 16:23, Stefan Lippers-Hollmann wrote: > > Hi > > > > On Sunday 10 April 2011, Anton Ivanov wrote: > > > >> On 04/10/11 00:55, Ben Hutchings wrote: > >> > >>> On Fri, 2011-04-08 at 13:39 +0100, Anton Ivanov wrote: [...] > >> Yes. No effect. ath still reads from eeprom. > >> > > The EEPROM settings are authoritative, you can only restrict the > > regulatory settings further to aid regulatory compliance in different > > regions, but never relax them. Tools like crda always intersect the > > EEPROM's (OTP in newer chipset generations) with the chosen regulatory > > domain as provided by wireless-regdb or the in-kernel regdb; regulatory > > hints like IEEE 802.11d may also restrict the allowed frequencies even > > further. > > > > http://wireless.kernel.org/en/users/Drivers/ath#Regulatory > > > > This is intended beaviour and required for FCC compliance (keep in mind > > that calibration data is also only validated for the given regdomain), > > not a bug. > > > > So a card that returns only CN from EEPROM is basically intended to be > sold _ONLY_ in China. Right? [...]
Correct, it's arguably even illegal to sell in ETSI regions. Although it's technically a little more complex as Atheros groups regdom regions with identical mappings together[1], which makes reading the EEPROM based regulatory domain code a bit strange (the alphabetically first match corresponding to the regdom group gets printed to dmesg). In your particular case, with a 2.4 GHz-only AR2417 PHY, 0x52 (APL1_WORLD vs ETSI1_WORLD, GB) doesn't actually do any harm, as 'CN' allows channel 1-13 just as well as the most permissive regdomains (ch14 in Japan is only allowed for CSMA/CA == 11 MBit/s, not the more common OFDM rates (>= 54 MBit/s)). So even though your device is wrongly programmed, it doesn't actually limit your abilities (unless you'd add an additional 5 GHz capable card, which would suffer from an 'unfortunate' intersection) - and neither allows you to access non-public frequency bands. This situation would be seriously worse (both technically and legally) for 5 GHz operations, but your device doesn't support that anyways. country CN: (2402 - 2482 @ 40), (N/A, 20) (5735 - 5835 @ 40), (N/A, 30) country GB: (2402 - 2482 @ 40), (N/A, 20) (5170 - 5250 @ 40), (N/A, 20) (5250 - 5330 @ 40), (N/A, 20), DFS (5490 - 5710 @ 40), (N/A, 27), DFS However I'm aware of the sad truth that most commonly sold cards are wrongly programmed for CN or (worse for 2.4 GHz operations) US... Regards Stefan Lippers-Hollmann [1] http://wireless.kernel.org/en/users/Drivers/ath#line-28 -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org