Re: ath6kl_mgmt_tx with NULL chan

[Kalle Valo <kvalo@qca.qualcomm.com>]

Antonio Quartulli <ordex@autistici.org> writes:

> On Mon, Jun 03, 2013 at 05:04:08PM +0200, Nicolas Cavallari wrote:
>> On 03/06/2013 16:59, Johannes Berg wrote:
>> > On Mon, 2013-06-03 at 08:39 +0200, Antonio Quartulli wrote:
>> >> From: Antonio Quartulli <antonio@open-mesh.com>
>> >>
>> >> Users may want to send a frame on the current channel
>> >> without specifying it.
>> >>
>> >> Make mgmt_tx pass a NULL channel to mac80211 if none has
>> >> been specified by the user.
>> > 
>> > cfg80211 isn't just a mac80211 frontend ... ;-)
>> > 
>> > Also, as Nicolas said, ath6kl_mgmt_tx() will crash after this patch if
>> > it's called in AP mode w/o a channel, so you need to think about that.
>> 
>> It will crash unconditionally. All ath6kl_mgmt_tx()'s code paths access
>> chan->center_freq at some point.
>
> Hello Nicolas,
> I'm also CCing Kalle Valo since get_maintainer.pl told me he is the guy for
> these kind of questions :-)
>
> I'm looking at ath6kl_mgmt_tx() in ath6kl/cfg80211.c and I've seen that the
> currently "configured" frequency can be obtained by reading the
> ath6kl_vif->ch_hint field.
>
> But, is this correct?

I did a quick look. To me using ch_hint looks correct.

> I couldn't see any real relation between the ch_hint field and the
> real frequency (probably because a lot of logic is hidden to the
> driver). I could only understand that the ch_hint field stores the
> frequency passed as parameter during the connection, but I have found
> no guarantee that this is the really used one.

Can you be more specific, please?

To me it looks that ch_hint is used both with ath6kl_wmi_reconnect_cmd()
and ath6kl_wmi_connect_cmd() commands, which both are used to connect to
a network. I don't see any other variables used for specifying the
frequency to the firmware. But I could just be blind...

-- 
Kalle Valo