On Tue, Dec 1, 2009 at 10:27 AM, Johannes Berg <johannes@xxxxxxxxxxxxxxxx> wrote: > On Tue, 2009-12-01 at 13:17 -0500, Pavel Roskin wrote: >> On Tue, 2009-12-01 at 18:29 +0100, Johannes Berg wrote: >> > In some situations it is required that a system be >> > configured with no support for 40 MHz channels in >> > the 2.4 GHz band. Rather than imposing any such >> > restrictions on everybody, allow configuration a >> > system like that with a module parameter. It is >> > writable at runtime but only takes effect at the >> > time of the next association. >> >> That looks like a hack to me. >> >> Maybe it should be treated like other CRDA flags? In fact, you can find >> this in dbparse.py in the wireless-regdb sources: >> >> # hole at bit 9. FIXME: Where is NO-HT40 defined? >> 'NO-HT40': 1<<10, >> >> However, there are no other references to NO-HT40 in the wireless-regdb >> or CRDA sources. I assume it's not implemented. > > It's not a regulatory requirement, it's a coexistence requirement. To extend this text a little more, me and Johannes had reviewed usage of a NO-HT40 flag for regulatory purposes a while back. It was used mainly on the old Atheros HAL regulatory code and upon a lot of review even with our own regulatory folks determined that in fact there was no specific rules about disallowing 40 MHz, but that when this was disallowed it can be implied by the frequency range not fitting a 40 MHz channel. This is currently computed dynamically now on cfg80211 and its results are outputed through the file: /sys/kernel/debug/ieee80211/phy0/ht40allow_map Countries that do not allow HT40 were working on allowing it anyway so as of now I don't think there are countries that disallow it unless its implied by the frequency ranges allowed. Luis -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
