https://gerrit.asterisk.org/c/asterisk/+/13527 Patch Set 1 testing conditions :

Software
--------

Asterisk 16.7.0 + sig_pri.c Change Set 13527 Patch Set 1:
(ast_queue_hangup + ast_set_hangupsource) before ast_channel_unlock

Hardware
--------

TE820 with span 4 (euroisdn pri_net) connected to span 8 (euroisdn pri_cpe) with a crossover cable
Dell Server

Configuration
-------------

extensions.conf:
- call generation with call files towards span 4
- call answer (on span 8) with fast hangup (50ms)

; Call file processing
[hsrc_originator]
exten = s,1,NoCDR()
same = n,Answer()
same = n,Wait(10)
same = n,Hangup()
exten = h,1,Set(CDR(hangupsource)=${CHANNEL(hangupsource)})

; Outgoing call to span 4
[hsrc]
exten = _X!,1,Dial(DAHDI/g4/1)
exten = h,1,Set(CDR(hangupsource)=${CHANNEL(hangupsource)})

; Incoming call from span 8
[dahdi_in]
exten = 1,1,Answer()
same = n,Wait(0.05)
same = n,Hangup()

Calls and 'pri show span' requests
----------------------------------

Call generation:
- call files generation, approx 10 calls/s

while true; do \
	FILE=dahdi-$(date +"%T.%N").call; \
	echo -e "Channel: Local/s@hsrc_originator\\nContext:hsrc\\nExtension: 1" >/tmp/$$-$FILE && \
		chown tulipd:tulipd /tmp/$$-$FILE && \
		mv /tmp/$$-$FILE /var/spool/asterisk/outgoing/$FILE; \
	sleep 0.1; \
	done

'pri show span' requests:
- 'pri show span 4' every 1 s

while true; do rasterisk -x 'pri show span 4'; sleep 1; done