On 10 May 2013 00:26, Johannes Berg <johannes@xxxxxxxxxxxxxxxx> wrote: > On Thu, 2013-05-09 at 20:10 +0200, a@pandem0nium wrote: > >> Comments: >> * Is there any special requirement for handling beacons? For example, >> rates are halfed or quartered, but some rates could not be represented >> in the rate IEs. For example, 2.25 mbit/s can not be represented as >> multiple of 500 kbps. >> * therefore, all rates are handled like the corresponding 20 MHz >> rates >> internally, which makes a lot of things easier (no changes required >> for rc-algos, beacon creation, etc...). We might consider adjusting >> the >> output of rates for nl80211 or radiotap, though. > > This seems completely wrong, since Clause 18 says: > > The OFDM system also provides a “half-clocked” operation using > 10 MHz channel spacings with data communications capabilities of > 3, 4.5, 6, 9, 12, 18, 24, and 27 Mb/s. The support of > transmitting and receiving at data rates of 3, 6, and 12 Mb/s is > mandatory when using 10 MHz channel spacing. The half-clocked > operation doubles symbol times and clear channel assessment > (CCA) times when using 10 MHz channel spacing. The regulatory > requirements and information regarding use of this OFDM PHY are > in Annex D and Annex E. > > IOW, it treats the rates as actually the rate they should be. Besides, > what's so hard about rounding up? (8.4.2.4) > > and bits 6 to 0 are set to the data rate, if necessary rounded > up to the next 500kb/s, in units of 500 kb/s. > > > I also think you really need to handle this. If you just want a hack for > 5/10 MHz, you can put it into drivers' debugfs, if not, then it should > be done properly :-) I think net80211 from FreeBSD and madwifi do this. Ie, they advertise the half and quarter rate speeds as their real speeds at half/quarter rate. If anything, interoperability would be nice. Adrian -- 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
