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Subject: Re: [PATCH 7/9] mac80211: add flags for STBC (Space-Time Block
 Coding)
From: Johannes Berg <johannes@sipsolutions.net>
To: Felix Fietkau <nbd@openwrt.org>
Cc: linux-wireless@vger.kernel.org, linville@tuxdriver.com,
	lrodriguez@atheros.com
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Date: Mon, 19 Apr 2010 10:59:42 +0200
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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?

johannes