Return-path: Received: from nbd.name ([88.198.39.176]:50248 "EHLO ds10.nbd.name" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752125Ab0DSIqE (ORCPT ); Mon, 19 Apr 2010 04:46:04 -0400 Message-ID: <4BCC1844.4030607@openwrt.org> Date: Mon, 19 Apr 2010 10:45:56 +0200 From: Felix Fietkau MIME-Version: 1.0 To: Johannes Berg CC: linux-wireless@vger.kernel.org, linville@tuxdriver.com, lrodriguez@atheros.com Subject: Re: [PATCH 7/9] mac80211: add flags for STBC (Space-Time Block Coding) References: <1271602602-8538-1-git-send-email-nbd@openwrt.org> <1271602602-8538-2-git-send-email-nbd@openwrt.org> <1271602602-8538-3-git-send-email-nbd@openwrt.org> <1271602602-8538-4-git-send-email-nbd@openwrt.org> <1271602602-8538-5-git-send-email-nbd@openwrt.org> <1271602602-8538-6-git-send-email-nbd@openwrt.org> <1271602602-8538-7-git-send-email-nbd@openwrt.org> <1271606009.3873.0.camel@jlt3.sipsolutions.net> <4BCB2DB3.3020700@openwrt.org> <1271656677.3873.5.camel@jlt3.sipsolutions.net> In-Reply-To: <1271656677.3873.5.camel@jlt3.sipsolutions.net> Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 2010-04-19 7:57 AM, Johannes Berg wrote: > On Sun, 2010-04-18 at 18:05 +0200, Felix Fietkau wrote: > >> >> + * @IEEE80211_TX_CTL_STBC: tells the driver to use Space-Time Block Coding >> >> + * (STBC) for this frame. >> >> */ >> >> enum mac80211_tx_control_flags { >> >> IEEE80211_TX_CTL_REQ_TX_STATUS = BIT(0), >> >> @@ -299,6 +301,7 @@ enum mac80211_tx_control_flags { >> >> IEEE80211_TX_INTFL_HAS_RADIOTAP = BIT(20), >> >> IEEE80211_TX_INTFL_NL80211_FRAME_TX = BIT(21), >> >> IEEE80211_TX_CTL_LDPC = BIT(22), >> >> + IEEE80211_TX_CTL_STBC = BIT(23), >> > >> > What if the # of streams is different? That doesn't look sufficient. > >> Hm, you're right. I initially thought the combination of the MCS index >> and the STBC flag would be enough, but there are still some corner cases. > > Hm actually I guess that should be sufficient? What corner case are you > thinking of? Support for multi-rate retry and STBC with more than one stream on one side, using rates from both MCS0-7 and MCS8-15 in the rate series. Rx STBC for only one stream on the other side. - Felix