Create a new task to handle 802.11n channel width changes.

Currently, a channel width change updates the 802.11n HT info data in
net80211 but it doesn't trigger any device changes.  So the device
driver may decide that HT40 frames can be transmitted but the last
device channel set only had HT20 set.

Now, a task is scheduled so a hardware reset or change isn't done
during any active ongoing RX. It also means that it's serialised
with the other task operations (eg channel change.)

This isn't the final incantation of this work, see below.

For now, any unmodified drivers will simply receive a channel
change log entry.  A subsequent patch to ath(4) will introduce
some basic channel change handling (by resetting the NIC.)
Other NICs may need to update their rate control information.

TODO:

* There's still a small window at the present moment where the
  channel width has been updated but the task hasn't been fired.
  The final version of this should likely pass in a channel width
  field to the driver and let the driver atomically do whatever
  it needs to before changing the channel.

PR:		kern/166286

1 files changed, 5 insertions, 0 deletions

diff --git a/sys/net80211/ieee80211_var.h b/sys/net80211/ieee80211_var.h
index feb9fb8..77e67aa 100644
--- a/sys/net80211/ieee80211_var.h
+++ b/sys/net80211/ieee80211_var.h
@@ -130,6 +130,7 @@ struct ieee80211com {
 	struct task		ic_mcast_task;	/* deferred mcast update */
 	struct task		ic_chan_task;	/* deferred channel change */
 	struct task		ic_bmiss_task;	/* deferred beacon miss hndlr */
+	struct task		ic_chw_task;	/* deferred HT CHW update */
 
 	uint32_t		ic_flags;	/* state flags */
 	uint32_t		ic_flags_ext;	/* extended state flags */
@@ -322,6 +323,10 @@ struct ieee80211com {
 				    int batimeout, int baseqctl);
 	void			(*ic_ampdu_rx_stop)(struct ieee80211_node *,
 				    struct ieee80211_rx_ampdu *);
+
+	/* The channel width has changed (20<->2040) */
+	void			(*ic_update_chw)(struct ieee80211com *);
+
 	uint64_t		ic_spare[7];
 };