How to modify channel width with ath9k driver?

[ghostrain]

Hello there!

I am hacking into linux wireless driver to modify channel width dynamicly. Basicly, what I want to do is:

1) initially, the client uses 20MHz channel width and receives data at 20MHz rates from the AP

2) then, the client switches to 40MHz channel width and receives data from AP at 40MHz rates

What I have done now is:

1) in 20MHz mode, client sends an action frame to AP requesting using 40MHz rates (I used the Notify Channel Width field defined in 11n spec)

2) on receiving request, AP sends back an ACK frame (what I want to but haven't done here is changing AP's channel width to 40MHz)

3) client receives the ACK (and what I want to but haven't done is changing client's channel width from 20MHz to 40MHz)

action frame is received and handled in ieee80211_rx_h_action() in net/mac80211/rx.c

I truly appreciate your time and suggestions!
Thanks!