OsmoBSC lchan allocator doesn't skip CBCH sub-slots on SDCCH allocation
When CBCH is active, this will consume sub-slot 2 of the SDCCH on that timeslot. I believe the old lchan allocator somehow skipped them. I couldn't find any related code in the current OsmoBSC codebase, so I hacked up a WIP/untested patch for that: https://gerrit.osmocom.org/#/c/osmo-bsc/+/10868/
It might be more elegant to somehow get that lchan's FSM into a state != UNUSED and avoid the extra check function...