dyn TS: allow any pchan type changes, fix for gprs mode none

In rsl_chan_activate_lchan(), remove a condition to also allow switching pchan
modes when not in PDCH mode, which is actually not needed and would hinder
switching from pchan=NONE or between TCH/F <-> TCH/H.

Refactor the part where lchan_alloc() decides to switch a pchan mode into a
separate function, ts_usable_as_pchan(), which transparently checks both dyn TS
kinds for:

- Already in switchover? (missing check for ip.access style dyn TS)
- Is the lchan->state in error? (missing check for ip.access style dyn TS)
- Switch from pchan=NONE? (missing feature for Osmocom style dyn TS, for proper
  handling with gprs mode none)
- Switch between TCH/F <-> TCH/H when all subslots are unused?
  (missing feature for Osmocom style dyn TS, also useful for gprs mode none)

Always pass the desired pchan in the dyn_as_pchan argument to the _lc_find_*
functions to make switchover decisions transparent. Use the _lc_dyn_find_bts()
function for ip.access style dyn TS for the same reason.

Related: OS#3244
Change-Id: I72d5d833b186b1e1925d513885b405d8c19aa496

1 files changed, 0 insertions, 1 deletions

diff --git a/src/libbsc/abis_rsl.c b/src/libbsc/abis_rsl.c
index e6d0cea96..167ef6bfb 100644
--- a/src/libbsc/abis_rsl.c
+++ b/src/libbsc/abis_rsl.c
@@ -569,7 +569,6 @@ int rsl_chan_activate_lchan(struct gsm_lchan *lchan, uint8_t act_type,
 	 * released.
 	 */
 	if (lchan->ts->pchan == GSM_PCHAN_TCH_F_TCH_H_PDCH
-	    && lchan->ts->dyn.pchan_is == GSM_PCHAN_PDCH
 	    && lchan->ts->dyn.pchan_is == lchan->ts->dyn.pchan_want) {
 		enum gsm_phys_chan_config pchan_want;
 		pchan_want = pchan_for_lchant(lchan->type);