Multiple vifs and HT v/s non-HT.
We found something fun while playing with HT mode:
We had some vifs associated with an AP with HT enabled, and other VIFS to an AP with HT disabled.
They managed to associate, but with slow rates and for whatever reason, nothing is able to send traffic. I would have expected one set or the other would be able to send traffic.
The ath9k hardware ended up in HT mode according to ath9k debugfs wiphy file, but that was probably just luck.
I'm not too sure how to ensure this mixed-mode HT scenario doesn't happen at this point...
Thanks,
Ben
Signature · 2 lines
Ben Greear <[email protected]> Candela Technologies Inc http://www.candelatech.com
Quoted 10 lines · Ben Greear
We found something fun while playing with HT mode:
We had some vifs associated with an AP with HT enabled, and other VIFS to an AP with HT disabled.
They managed to associate, but with slow rates and for whatever reason, nothing is able to send traffic. I would have expected one set or the other would be able to send traffic.
Quoted 6 lines
The ath9k hardware ended up in HT mode according to ath9k debugfs wiphy file, but that was probably just luck.
I'm not too sure how to ensure this mixed-mode HT scenario doesn't happen at this point...
So that patch you sent addressed this?
johannes
Quoted 11 lines · Johannes Berg
Quoted 10 lines · Ben Greear
We found something fun while playing with HT mode:
We had some vifs associated with an AP with HT enabled, and other VIFS to an AP with HT disabled.
They managed to associate, but with slow rates and for whatever reason, nothing is able to send traffic. I would have expected one set or the other would be able to send traffic.
Quoted 8 lines
Quoted 6 lines
The ath9k hardware ended up in HT mode according to ath9k debugfs wiphy file, but that was probably just luck.
I'm not too sure how to ensure this mixed-mode HT scenario doesn't happen at this point...
So that patch you sent addressed this?
Well, I could no longer (easily?) reproduce the problem, but to be honest, I don't see how my changes could have fixed the problem that I saw. I still think that patch is useful and could fix other problems, however.
I ran 30 STAs w/out HT and 30 with all night, about 175kbps UDP tx + rx on each interface, and it ran OK.
But, there may still be issues/races with initial setup and state transitions.
At the least, the set-channel-type method should do WARN_ON_ONCE instead of WARN_ON if you have HT40+ on some VIFs and HT40- on others. I was also thinking that the first vif(s) to associate on a channel-type should win..and just fail to set the channel type to something invalid (ie, ht40- -> ht40+) in that case. Otherwise, I think you would get endless flapping.
Thanks,
Ben
Quoted 7 lines
johannes
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Signature · 2 lines
Ben Greear <[email protected]> Candela Technologies Inc http://www.candelatech.com