Hello Jenkins Builder,

I'd like you to reexamine a change. Please visit

https://gerrit.osmocom.org/c/osmo-bts/+/35095?usp=email

to look at the new patch set (#3).

Change subject: early-IA: use the correct TRX ......................................................................

early-IA: use the correct TRX

In early-Immediate-Assignment, the BSC sends the IMM ASS message directly after it sent the Channel Activation message, and osmo-bts should cache it until the Channel Activation is complete.

So far the code had a bug: it assumed that the lchan was on the same TRX where the IMM ASS is transmitted -- but actually, 'trx' refers to the BCCH channel's TRX, i.e. always c0.

Instead, look up the correct TRX by the ARFCN in the IMM ASS message.

Now, when frequency hopping is enabled, there will be no ARFCN in the IMM ASS message, hence this fix does not work with frequency hopping. Related osmo-bsc patch disallows this combination.

(To also support frequency hopping, osmo-bsc would need to modify the RSL protocol: send the IMM ASS message as a custom IE directly as part of the Channel Activation. Then it is always possible to correllate the IMM ASS with a specific trx and lchan, no matter what information it contains. However, early-IA is a "bad" feature in itself as it "promotes" having high latency on Abis. It seems unnecessary to do extra work to also support this odd use case for frequency hopping.)

Related: osmo-bsc I8d375e5155be7b53034d5c0be5566d2f33af5db0 Related: SYS#6655 Change-Id: Id9a930e5c67122812b229dc27ea2bfe246b67611 --- M src/common/rsl.c 1 file changed, 67 insertions(+), 9 deletions(-)

git pull ssh://gerrit.osmocom.org:29418/osmo-bts refs/changes/95/35095/3