How to change channel type b/t HT20 and HT40 in driver code (ath9k)?

Hello Developers!

I've been trying to implement Notify Channel Width for linux wireless compat driver.

One thing need to be done is to change station's channel type between ht20 and ht40 without interrupting data transmission.

What I can do now is switching between ht20 rates and ht40 rates, but not channel type. For ap side, ieee80211_set_channel_type() works fine when called in function ieee80211_rx_h_action() to change ap channel type between ht20 and ht40. But on station side, I couldn't find a proper function within which to call ieee80211_set_channel_type(), and all my try caused kernel panic. Even calling ieee80211_set_channel_type() exactly the same way I do with ap on station side will crash system also.

Could anybody give some hint on possible way (e.g. API) to change channel type between ht20 and ht40 on station side, please?

Thanks in advance!

Wen