Return-path: Received: from mail-wi0-f180.google.com ([209.85.212.180]:35855 "EHLO mail-wi0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751301AbaIXPFv convert rfc822-to-8bit (ORCPT ); Wed, 24 Sep 2014 11:05:51 -0400 Received: by mail-wi0-f180.google.com with SMTP id q5so7490988wiv.7 for ; Wed, 24 Sep 2014 08:05:50 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <5422D6CF.10408@candelatech.com> References: <1411518383-32634-1-git-send-email-greearb@candelatech.com> <1411518383-32634-2-git-send-email-greearb@candelatech.com> <5422D6CF.10408@candelatech.com> Date: Wed, 24 Sep 2014 17:05:50 +0200 Message-ID: (sfid-20140924_170556_912012_29F01328) Subject: Re: [RFC 2/2] ath10k: re-config ht_caps when chainmask is modified. From: Michal Kazior To: Ben Greear Cc: linux-wireless , "ath10k@lists.infradead.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 24 September 2014 16:35, Ben Greear wrote: > On 09/24/2014 12:51 AM, Michal Kazior wrote: >> On 24 September 2014 02:26, wrote: >> [...] >>> >>> +static struct ieee80211_sta_vht_cap ath10k_create_vht_cap(struct ath10k >>> *ar, >>> + bool >>> use_cfg_chains) >>> { >>> struct ieee80211_sta_vht_cap vht_cap = {0}; >>> u16 mcs_map; >>> int i; >>> + int nrf = ar->num_rf_chains; >>> + >>> + if (use_cfg_chains && ar->cfg_tx_chainmask) >>> + nrf = get_nss_from_chainmask(ar->cfg_tx_chainmask); >> >> >> Is use_cfg_chains really necessary here? Is setting tx/rx chainmask to >> 0x0 make any sense at all? Shouldn't we deny it or make it fallback to >> the supported tx/rx chainmask values? > > It would cause the logic to flip back to the defaults, so seems mildly > useful. I'm not sure > upper layers would ever let it be < 1 though. 0 is a valid argument as far as upper layers are concerned and should be treated as "use all available antennas" (see `iw list` output before ever setting antenna, after setting to, e.g. 1 and then to 0). This implies current set_antenna() implementation is actually buggy (pdev param should involve using supp_tx/rx_chainmask). Your assumption in recent patches is also incorrect as antenna mask = 0 should imply max nss, not 1. Michał