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: Ben Greear <greearb@candelatech.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index dfa752e..e059b3a 100644 (file)
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -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;
 
-       /* check that channel matches the right operating channel */
-       if (local->hw.conf.channel->center_freq !=
-           ieee80211_channel_to_frequency(hti->control_chan, sband->band))
-               enable_ht = false;
+       if (enable_ht) {
+               hti_cfreq = ieee80211_channel_to_frequency(hti->control_chan,
+                                                          sband->band);
+               /* check that channel matches the right operating channel */
+               if (local->hw.conf.channel->center_freq != hti_cfreq) {
+                       /* Some APs mess this up, evidently.
+                        * Netgear WNDR3700 sometimes reports 4 higher than
+                        * the actual channel, for instance.
+                        */
+                       printk(KERN_DEBUG
+                              "%s: Wrong control channel in association"
+                              " response: configured center-freq: %d"
+                              " hti-cfreq: %d  hti->control_chan: %d"
+                              " band: %d.  Disabling HT.\n",
+                              sdata->name,
+                              local->hw.conf.channel->center_freq,
+                              hti_cfreq, hti->control_chan,
+                              sband->band);
+                       enable_ht = false;
+               }
+       }
 
        if (enable_ht) {
                channel_type = NL80211_CHAN_HT20;