On Wed July 28 2010 01:47:34 Luis R. Rodriguez wrote: > On Tue, Jul 27, 2010 at 9:39 AM, Felix Fietkau <nbd@xxxxxxxxxxx> wrote: > > On 2010-07-27 6:19 PM, Luis R. Rodriguez wrote: > >>> + * @NL80211_ATTR_WIPHY_ANTENNA_TX: Bitmap of allowed antennas for > >>> transmitting. + * Each bit represents one antenna, starting with > >>> antenna 1 at the first + * bit. If the bitmap is zero (0), the TX > >>> antenna follows RX diversity. > >> > >> What about for 802.11n? What if you want to disable TX? > > > > Disabling tx shouldn't be handled by the antenna setting, IMHO. > > > >>> + * If multiple antennas are selected all selected antennas have to > >>> be used + * for transmitting (801.11n multiple TX chains). > >> > >> I rather call this TX / RX chainmask then. > > > > Well, for legacy hardware, these aren't really chains, as there is only > > one rx and one tx path, just with switching onto multiple antennas. > > > >>> + * Drivers may reject configurations they cannot support. > >>> + * > >>> + * @NL80211_ATTR_WIPHY_ANTENNA_RX: Bitmap of allowed antennas for > >>> receiving. + * Each bit represents one antenna, starting with > >>> antenna 1 at the first + * bit. If multiple antennas are selected > >>> in the bitmap, 802.11n devices + * should use multiple RX chains > >>> on these antennas, while non-802.11n + * drivers should use > >>> antenna diversity between these antennas. > >> > >> What about TX beamforming, and STBC? > > > > Disabling one antenna/chain on a two-chain device would naturally > > disable TxBF and STBC as well, since it limits the number of available > > chains. The driver should simply act as if the disabled chains didn't > > exist. > > That would work. > > >> Unless 802.11n is completely dealt with I really prefer this patch to > >> only address legacy. Otherwise I see sloppyness and inconsistencies on > >> supporting this feature throughout different drivers. I'd like to > >> avoid that at all costs on nl80211. What you are trying to address is > >> legacy antenna setup, not 802.11n RX/TX chainmask dynamic settings so > >> I'd really try to avoid it unless you really want to address all > >> aspects of chain configuration for 802.11n and even then what I'm > >> leading on to say is I think you'll see if you try to address both it > >> just gets messy. > > > > I think 802.11n is already completely dealt with if you treat this as > > the chainmask on 11n devices. > > Its fine by me if the above cases are also embedded into the > documentation, just don't want these questions lingering. I can't > think of other 802.11n special cases. thanks felix :) luis, could you tell me what exactly you would want to include in the documentation? bruno -- 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
