DSP TCH task : time to get/put FAACH
246tnt at gmail.com
Fri Oct 22 21:47:16 UTC 2010
Some news from the front on this :
> * When to put / read data for FACCH.
Ok, I've accepted it's a requirement of the DSP ... (I looked into the
DSP code to make sure it was) ...
> * TCH/H support: AFAIK, I did everything that should be required for
> it to work:
After fixing some bugs, and some debugging sessions with steve|m (thanks btw :):
- Half subchannel 0: Call establishement / FACCH works. But no audio.
Steve confirmed that audio _is_ sent from the mobile, by recording it
with the racal and then playing it back on a phone with stock
firmware. So it's a downlink issue ...
- Half subchannel 1: FACCH works, but can't establish a call anyway
... The problem seems to be in the upper layer. My current theory is
that we hit some race condition somewhere and the slight timing
difference between subchannel 0 and subchannel 1 triggers it in one
case but not the other ...
Basically on FACCH:
- we send the SABM
- we get the UA back
- we send the ASSIGNEMENT COMPLETE N(S)=0, N(R)=0
- we get RR N(R)=1
- we send 3 times RR N(R)=0 ( <-- this is weird )
- then lapdm doesn't xmit anything from the upper layer anymore.
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