[PATCH 01/10] carl9170: mac80211: enable Short Guard Interval for 20 MHz

[Masi Osmani <mas-i@hotmail.de>]

The AR9170 hardware supports Short Guard Interval (400ns) for both
20 MHz and 40 MHz channel widths.  SGI_40 was already advertised in
the HT capabilities, but SGI_20 was missing.  This reduces the OFDM
symbol duration from 800ns to 400ns on 20 MHz channels, increasing
the maximum PHY rate from 130 Mbps to 144.4 Mbps (MCS 15, 2SS).

ath9k (the PCI sibling for the same AR9xxx chipset family) has
always advertised both SGI_20 and SGI_40.

Signed-off-by: Masi Osmani <mas-i@hotmail.de>
---
 drivers/net/wireless/ath/carl9170/main.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/wireless/ath/carl9170/main.c b/drivers/net/wireless/ath/carl9170/main.c
index a7a9345..aa7e481 100644
--- a/drivers/net/wireless/ath/carl9170/main.c
+++ b/drivers/net/wireless/ath/carl9170/main.c
@@ -154,6 +154,7 @@ static struct ieee80211_channel carl9170_5ghz_chantable[] = {
 	.cap		= IEEE80211_HT_CAP_MAX_AMSDU |			\
 			  IEEE80211_HT_CAP_SUP_WIDTH_20_40 |		\
 			  IEEE80211_HT_CAP_SGI_40 |			\
+			  IEEE80211_HT_CAP_SGI_20 |			\
 			  IEEE80211_HT_CAP_DSSSCCK40 |			\
 			  IEEE80211_HT_CAP_SM_PS,			\
 	.ampdu_factor	= IEEE80211_HT_MAX_AMPDU_64K,			\
-- 
2.51.0