[PATCH] hostapd: Don't force HT Mixed Mode for non-GF STAs

Helmut Schaa helmut.schaa
Wed Mar 2 00:37:11 PST 2011

Currently hostapd will force HT Mixed Mode if at least one non-GF STA is
associated. This will force _all_ HT transmissions to be protected.

802.11n-2009 doesn't require HT Mixed Mode to be used in case of non-GF
STAs but instead the HT information element contains a flag if non-GF
STAs are present. All STAs are required to protect GF transmissions in
that case. Hence, setting HT Mixed mode if non-GF STAs are present is

Signed-off-by: Helmut Schaa <helmut.schaa at googlemail.com>
 src/ap/ieee802_11_ht.c |    7 +------
 1 files changed, 1 insertions(+), 6 deletions(-)

diff --git a/src/ap/ieee802_11_ht.c b/src/ap/ieee802_11_ht.c
index acb85fe..73e9a9f 100644
--- a/src/ap/ieee802_11_ht.c
+++ b/src/ap/ieee802_11_ht.c
@@ -131,13 +131,8 @@ int hostapd_ht_operation_update(struct hostapd_iface *iface)
-	/* Note: currently we switch to the MIXED op mode if HT non-greenfield
-	 * station is associated. Probably it's a theoretical case, since
-	 * it looks like all known HT STAs support greenfield.
-	 */
 	new_op_mode = 0;
-	if (iface->num_sta_no_ht ||
-	    (iface->ht_op_mode & HT_INFO_OPERATION_MODE_NON_GF_DEVS_PRESENT))
+	if (iface->num_sta_no_ht)
 		new_op_mode = OP_MODE_MIXED;
 	else if ((iface->conf->ht_capab & HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET)
 		 && iface->num_sta_ht_20mhz)

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