lchan: Release channel in case of late activation ack

In case of the sysmoBTS and receiving a channel activation ack on a channel
that was marked as broken, release it again.

Use a normal release without SACCH deactivation and release the rqd_ta data.

Also add a local variable 'ts' to shorten some lines.

The typical situation where this would occur is with high latency between BTS
and BSC (or NITB). If a channel activation ack does not arrive in time, a
channel is marked broken, and never recovers after that. This patch will
release the channel again, which will remove the BROKEN_UNUSABLE state and
makes lchan available again. Reported by Rhizomatica.

However, in case of packet loss, i.e. when the channel activation ack never
arrives at the BSC, this patch does not provide a resolution of the
BROKEN_UNUSABLE state.

On dynamic timeslots: clearing the dyn ts state could possibly happen in
lchan_free() instead of in rsl_rx_chan_act_ack(). That's to be done in a
separate patch, if at all.

Tweaked-By: nhofmeyr
Change-Id: I63dc0deaf15ba7c21e20b1e0c7b85f0437e183ed
1 file changed
tree: 1e7af2cb34677332c8c3d2f31028aa512d4cca3a
  1. contrib/
  2. debian/
  3. openbsc/
  4. .gitignore
  5. .gitreview
  6. .mailmap