mac80211: Be more careful when changing channels.

If we cannot set the channel type, set the channel back to the
original.

Don't update the driver hardware if nothing actually changed.

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

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 4bc8a92..88b0884 100644 (file)
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1215,6 +1215,9 @@ static int ieee80211_set_channel(struct wiphy *wiphy,
 {
        struct ieee80211_local *local = wiphy_priv(wiphy);
        struct ieee80211_sub_if_data *sdata = NULL;
+       struct ieee80211_channel *old_oper;
+       enum nl80211_channel_type old_oper_type;
+       enum nl80211_channel_type old_vif_oper_type= NL80211_CHAN_NO_HT;
 
        if (netdev)
                sdata = IEEE80211_DEV_TO_SUB_IF(netdev);
@@ -1232,13 +1235,23 @@ static int ieee80211_set_channel(struct wiphy *wiphy,
                break;
        }
 
-       local->oper_channel = chan;
+       if (sdata)
+               old_vif_oper_type = sdata->vif.bss_conf.channel_type;
+       old_oper_type = local->_oper_channel_type;
 
        if (!ieee80211_set_channel_type(local, sdata, channel_type))
                return -EBUSY;
 
-       ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
-       if (sdata && sdata->vif.type != NL80211_IFTYPE_MONITOR)
+       old_oper = local->oper_channel;
+       local->oper_channel = chan;
+
+       /* Update driver if changes were actually made. */
+       if ((old_oper != local->oper_channel) ||
+           (old_oper_type != local->_oper_channel_type))
+               ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
+
+       if ((sdata && sdata->vif.type != NL80211_IFTYPE_MONITOR) &&
+           old_vif_oper_type != sdata->vif.bss_conf.channel_type)
                ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_HT);
 
        return 0;