Return-path: Received: from mail.allnet.de ([212.18.29.59]:25565 "EHLO mail.allnet.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754691Ab1K2Lwp (ORCPT ); Tue, 29 Nov 2011 06:52:45 -0500 Message-ID: <4ED4C789.8060701@allnet.de> (sfid-20111129_125258_741403_289EEE8F) Date: Tue, 29 Nov 2011 12:52:41 +0100 From: Daniel Golle MIME-Version: 1.0 To: Johannes Berg CC: "linux-wireless@vger.kernel.org" , "Luis R. Rodriguez" , Felix Fietkau Subject: Re: [PATCH v1 0/3] support for antenna configuration profiles References: <20111128161225.GA25430@localhost> (sfid-20111128_171757_078893_7ACF616B) <1322499145.4060.8.camel@jlt3.sipsolutions.net> In-Reply-To: <1322499145.4060.8.camel@jlt3.sipsolutions.net> Content-Type: text/plain; charset="UTF-8" Sender: linux-wireless-owner@vger.kernel.org List-ID: -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi Johannes, On 11/28/2011 05:52 PM, Johannes Berg wrote: > Can you remind us what it is you're trying to achieve? And why it can't > be done with the antenna selection API today? My idea is to have a generic API allowing the user to select configuration profiles for external LNA/mixers found in outdoor high-power appliances. I also first thought of just using the existing antenna selection API for that, but there are good reasons against that: * Antenna control API assumes that the allowed values for tx_ant and rx_ant are independent of each other. In high-power applications, this is not the case (i.e. you'll probably even damage the RX-part of your hardware when selecting the same path for RX and TX). Therefore simple bitmasks such as available_antennas_rx/tx won't do the job. * Both, external mixer and antenna control may be used together in MiMo applications, e.g. you may have antennas 0,1 which are controlled by the usual antenna selection API and additionally you got an external LNA/mixer which allows you to select either the built-in antenna-pair or an externally connected one. In my example, it looks like this +---------+ +-------+ | ---TXa--- | | WiFi ---RXa1-- ext. | | Chip ---RXa2-- LNA | |(AR9285) ......... mixer | +---------+ +-------+ You may still want to use antenna selection API to selected either RX-path 0 or 1 or both of the AR9285, additionally you want to select a profile for the external LNA/mixer. * As Adrian pointed out and I agree with, it's nice to give the user some information about the available configuration profiles, i.e. have user-parsable names and descriptions of the different configuration profiles (e.g. "built-in"/"external", "horizontal"/"vertical", ...) for the device. My current solution how things are done in ath9k is specific for the AR9285, but once there is a generic infrastructure for this in mac80211, it can be used for different solutions, e.g. ath5k-devices with a similar setup which control the ext.LNA/mixer using some GPIO PINs. In future we may also see devices with several directional MiMo beams and we want to select which one(s) to use. I hope things are more clear now. Cheers Daniel -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIcBAEBAgAGBQJO1MeFAAoJEDy9cKN/1Et0R14P/0boU8k9U1CHDJAQzLswT6aF ts9gE0DLvC10qSu15sdRWH516T9K3sFeq2LlSYx4ljV6G3Y1lECzlJjuhFk15ZW+ 5Q0dlofmEhmO3shdvODgrKcqIdmvDkxHRqlCXtYuEPsDKi3QWVEqj8nji588nORt wCDGxdNEl8HJYmKi8R+OsAZcypCylV5HFo/J+Xt9pgQmP6gtqGkF3s+KwiPLDFo8 BnusiD2aQOgqbSs/63t+yaapGLi2ATwFjgKOE/5DywyKUHPGT6e/SouGnWHVuEfA +Kq33fUm5C93VK9aBVg+hawj6LGB9DAizGlDaEUib4TVt6R23N5HaeOp4uI+T41K pjz3jQD6CsTM8Ypo3UvsRI+SWvacNPcmRqJMplOL7sc9pkNx1UatP/wE2/pRPfki X1t9Lw8cb6FIeRZAe+ftiDZN5TEvqOTXBMAYe4tsPMr/GZ/g5eubdZDiHVe0gkQ2 oIWFq8vnTX8UUP8jz0h4xkENsPoMHi6YwEFULIqdPfwEFqBXsxOCFPednZ5BU6ww KO9CQpMWqDhDtGsp5jsaC5s1K2Mo7w2hmfwMZjxy+wudftL7oe25niqlJZsTBKa9 j72u+XwqXkf4wmsbbaPmDOI93mqBcgSPOUtaEz3RRZbi4EFFQUZA1+bX0SMdUHxD 8oTrNnbFvv7ow1T2oQfy =I+el -----END PGP SIGNATURE-----