Question on commit: "Do not inform other virtual interfaces of scan results in all cases"

Jouni Malinen j at w1.fi
Sun Jun 1 04:39:07 EDT 2014


On Mon, May 12, 2014 at 08:04:35AM -0700, Ben Greear wrote:
> I have been trying to figure out why my multi-vif associations are taking too long,
> and it seems to be caused by this patch below.
> 
> In my case, I very much want to do multiple associations at a time.
> 
> So, question is:  Why was this considered harmful?  Maybe the problem
> only happens if two vifs are on different channels, or something like that?

I don't remember the exact issue that triggered this, but I think it was
based on a debug log that showed a concurrent P2P operation and a
non-P2P station interface trying to connect at the same time and one of
the operations either failing completely or at least delayed
significantly because of the steps that require exclusive radio control
(channel) being executed at the same time.

If I understood your later emails correctly, you have a configurable
parameter to allow these types of operations to occur at the same time.
That may be the safest options since it is clear that there are drivers
that issues with this. While different channels make this worse, I'm not
sure that is the only issue, i.e., just getting those commands for
different virtual interfaces may be enough to break (or at least block)
things.

-- 
Jouni Malinen                                            PGP id EFC895FA


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