From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from he.sipsolutions.net ([78.46.109.217]:38067 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751666Ab0DSJJO (ORCPT ); Mon, 19 Apr 2010 05:09:14 -0400 Subject: Re: [PATCH 7/9] mac80211: add flags for STBC (Space-Time Block Coding) From: Johannes Berg To: Felix Fietkau Cc: linux-wireless@vger.kernel.org, linville@tuxdriver.com, lrodriguez@atheros.com In-Reply-To: <4BCC1D1A.7020705@openwrt.org> 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> <4BCC1844.4030607@openwrt.org> <1271667582.3873.11.camel@jlt3.sipsolutions.net> <4BCC1D1A.7020705@openwrt.org> Content-Type: text/plain; charset="UTF-8" Date: Mon, 19 Apr 2010 11:09:10 +0200 Message-ID: <1271668150.3873.17.camel@jlt3.sipsolutions.net> Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Mon, 2010-04-19 at 11:06 +0200, Felix Fietkau wrote: > On 2010-04-19 10:59 AM, Johannes Berg wrote: > > On Mon, 2010-04-19 at 10:45 +0200, Felix Fietkau wrote: > >> 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. > > > > So the flag should be per rate entry instead, no? > Well, I think if we use two bits in the tx control flags, we don't need > it to be per rate entry. But then you can't probe stbc properly, can you? > We don't have any space left for more per rate entry flags ;) separate problem ;) johannes