Re: [PATCH] mac80211: fix channel type recalculation with HT and non-HT interfaces

[Johannes Berg <johannes@sipsolutions.net>]

On Fri, 2011-03-11 at 12:28 -0800, Ben Greear wrote:

> > But I'm not sure what you mean?
> >
> > With the fix, we go through and use the widest possible channel of all
> > interfaces. The only conflict can happen with HT40- and HT40+, but we
> > should never get into that situation since we can't have one interface
> > with HT40- and another with HT40+ at the same time to start with. Am I
> > missing something?
> 
> Maybe I'm missing something, but from what I can tell:
> 
> If we have two interfaces:
> 
> first interface is HT40, second is HT20:
>    -> superchan == HT20
> 
> first interface is HT20, second is HT40:
>    -> superchan == HT40
> 
> It seems wrong that the ordering would influence superchan before we go into
> the "switch (superchan)" logic.

Ah, you're right -- the real fix isn't this patch, but probably
something like this:

...
case NL..._NO_HT:
case NL_...HT20:
	if (channel_type < super_chan)
		break;
	superchan = channel_type;
	break;
...

johannes