Commit 172710bf authored by Ben Greear's avatar Ben Greear Committed by John W. Linville

mac80211: Warn users if HT fails because of freq mismatch.

I have a netgear WNDR3700 that appears to have an off-by-four
bug in how it fills out the hti->control_chan (I configure the
AP to channel 11, it reports 15 as control_chan).

Poke a message into the kernel logs to give users a
clue as to why they are not getting the expected
channel-type or rate.
Signed-off-by: default avatarBen Greear <>
Signed-off-by: default avatarJohn W. Linville <>
parent 0fa025f0
......@@ -161,6 +161,7 @@ static u32 ieee80211_enable_ht(struct ieee80211_sub_if_data *sdata,
struct ieee80211_supported_band *sband;
struct sta_info *sta;
u32 changed = 0;
int hti_cfreq;
u16 ht_opmode;
bool enable_ht = true;
enum nl80211_channel_type prev_chantype;
......@@ -174,10 +175,27 @@ static u32 ieee80211_enable_ht(struct ieee80211_sub_if_data *sdata,
if (!sband->ht_cap.ht_supported)
enable_ht = false;
if (enable_ht) {
hti_cfreq = ieee80211_channel_to_frequency(hti->control_chan,
/* check that channel matches the right operating channel */
if (local->>center_freq !=
ieee80211_channel_to_frequency(hti->control_chan, sband->band))
if (local->>center_freq != hti_cfreq) {
/* Some APs mess this up, evidently.
* Netgear WNDR3700 sometimes reports 4 higher than
* the actual channel, for instance.
"%s: Wrong control channel in association"
" response: configured center-freq: %d"
" hti-cfreq: %d hti->control_chan: %d"
" band: %d. Disabling HT.\n",
hti_cfreq, hti->control_chan,
enable_ht = false;
if (enable_ht) {
channel_type = NL80211_CHAN_HT20;
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