Re: [PATCH 7/9] mac80211: add flags for STBC (Space-Time Block Coding)

[Felix Fietkau <nbd@openwrt.org>]

On 2010-04-18 5:53 PM, Johannes Berg wrote:
> On Sun, 2010-04-18 at 16:56 +0200, Felix Fietkau wrote:
>> Signed-off-by: Felix Fietkau <nbd@openwrt.org>
>> ---
>>  include/linux/ieee80211.h |    1 +
>>  include/net/mac80211.h    |    3 +++
>>  2 files changed, 4 insertions(+), 0 deletions(-)
>> 
>> diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
>> index 1252ba1..97b2eae 100644
>> --- a/include/linux/ieee80211.h
>> +++ b/include/linux/ieee80211.h
>> @@ -876,6 +876,7 @@ struct ieee80211_ht_cap {
>>  #define IEEE80211_HT_CAP_SGI_40			0x0040
>>  #define IEEE80211_HT_CAP_TX_STBC		0x0080
>>  #define IEEE80211_HT_CAP_RX_STBC		0x0300
>> +#define		IEEE80211_HT_CAP_RX_STBC_SHIFT	8
>>  #define IEEE80211_HT_CAP_DELAY_BA		0x0400
>>  #define IEEE80211_HT_CAP_MAX_AMSDU		0x0800
>>  #define IEEE80211_HT_CAP_DSSSCCK40		0x1000
>> diff --git a/include/net/mac80211.h b/include/net/mac80211.h
>> index 75056dd..eadf794 100644
>> --- a/include/net/mac80211.h
>> +++ b/include/net/mac80211.h
>> @@ -275,6 +275,8 @@ struct ieee80211_bss_conf {
>>   *	MLME command (internal to mac80211 to figure out whether to send TX
>>   *	status to user space)
>>   * @IEEE80211_TX_CTL_LDPC: tells the driver to use LDPC for this frame
>> + * @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.
Want me to use BIT(23)|BIT(24) for this and add a shift, as with the HT
capability?

- Felix