iwn(4) hangs after r257133

[Stefan Farfeleder]

On Sun, Nov 10, 2013 at 10:48:48AM -0800, Adrian Chadd wrote:
> Right near the end there you have 'status 83' which means 'transmit
> failed, long retry hit' (the status codes are in if_iwnreg.h
> somewhere.) The retry count hit 16, which is the max set for the
> frame.
> 
> rate=80 (hex) is MCS0. So, you're seeing retransmits and failures at
> MCS0, which is a bad sign.
> 
> But, notice how AMRR increased it to MCS2 at a couple stages, and that
> _always_ fails. But AMRR waits for 10 frame transmits before it
> adjusts the rate up or down.
> 
> So yes, we do need to enable MRR again on iwn for things to behave
> better. There are other issues when you start doing larger amounts of
> traffic but I'll cover those later.what?
> 
> If someone wants to take a crack at correctly implementing the link
> quality table stuff again then please let me know. As I said before,
> the link quality table setup code is mostly sane. The problem is
> actually correctly setting 'linkq' to start at the selected rate, as
> linkq is an index into that table, not the initial rate.

Hi,

after some trial and error I found out that disabling AMPDU makes my
iwn0 usable again. Now I actually see the rate as reported by `list sta'
going up and down (mostly between 54M and 121M). Before it was always
fixed at 135M.

Could this be related?

Stefan