mac80211: allow disabling 40MHz on 2.4GHz
In some situations it is required that a system be
configured with no support for 40 MHz channels in
the 2.4 GHz band. Rather than imposing any such
restrictions on everybody, allow configuration a
system like that with a module parameter. It is
writable at runtime but only takes effect at the
time of the next association.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index e63aecbd..6fb3f71 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -881,6 +881,8 @@
void ieee80211_configure_filter(struct ieee80211_local *local);
u32 ieee80211_reset_erp_info(struct ieee80211_sub_if_data *sdata);
+extern bool ieee80211_disable_40mhz_24ghz;
+
/* STA code */
void ieee80211_sta_setup_sdata(struct ieee80211_sub_if_data *sdata);
int ieee80211_mgd_auth(struct ieee80211_sub_if_data *sdata,
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index e1293e8..25f5209 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -33,6 +33,12 @@
#include "cfg.h"
#include "debugfs.h"
+
+bool ieee80211_disable_40mhz_24ghz;
+module_param(ieee80211_disable_40mhz_24ghz, bool, 0644);
+MODULE_PARM_DESC(ieee80211_disable_40mhz_24ghz,
+ "Disable 40MHz support in the 2.4GHz band");
+
void ieee80211_configure_filter(struct ieee80211_local *local)
{
u64 mc;
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 0a762a9..a7472c9 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -400,6 +400,12 @@
/* determine capability flags */
+ if (ieee80211_disable_40mhz_24ghz &&
+ sband->band == IEEE80211_BAND_2GHZ) {
+ cap &= ~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
+ cap &= ~IEEE80211_HT_CAP_SGI_40;
+ }
+
switch (ht_info->ht_param & IEEE80211_HT_PARAM_CHA_SEC_OFFSET) {
case IEEE80211_HT_PARAM_CHA_SEC_ABOVE:
if (flags & IEEE80211_CHAN_NO_HT40PLUS) {
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 086ef62..acb6626 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -908,16 +908,24 @@
}
if (sband->ht_cap.ht_supported) {
- __le16 tmp = cpu_to_le16(sband->ht_cap.cap);
+ u16 cap = sband->ht_cap.cap;
+ __le16 tmp;
+
+ if (ieee80211_disable_40mhz_24ghz &&
+ sband->band == IEEE80211_BAND_2GHZ) {
+ cap &= ~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
+ cap &= ~IEEE80211_HT_CAP_SGI_40;
+ }
*pos++ = WLAN_EID_HT_CAPABILITY;
*pos++ = sizeof(struct ieee80211_ht_cap);
memset(pos, 0, sizeof(struct ieee80211_ht_cap));
+ tmp = cpu_to_le16(cap);
memcpy(pos, &tmp, sizeof(u16));
pos += sizeof(u16);
- /* TODO: needs a define here for << 2 */
*pos++ = sband->ht_cap.ampdu_factor |
- (sband->ht_cap.ampdu_density << 2);
+ (sband->ht_cap.ampdu_density <<
+ IEEE80211_HT_AMPDU_PARM_DENSITY_SHIFT);
memcpy(pos, &sband->ht_cap.mcs, sizeof(sband->ht_cap.mcs));
pos += sizeof(sband->ht_cap.mcs);
pos += 2 + 4 + 1; /* ext info, BF cap, antsel */