== PRISTINE production ppbconf.c, fresh-boot decisive run (run4) ==
PPBX2: DF-5513 ppb_request_bus owner-self-request test
PPBX2: DF-5513 control: non-owner DONTWAIT request -> 35 (expect EWOULDBLOCK=35)
PPBX2: DF-5513 REPRODUCED: owner re-requested with PPB_WAIT|PPB_NOINTR is STILL ASLEEP after 3s (tsleep "ppbreq", no PCATCH, no timeout -> sleeps forever in production; pcfclock_open has no HAVEBUS guard)
PPBX2: DF-5513 after ppb_release_bus: sleeper done=1 ret=0 (only an explicit release ever wakes it)

== variance across the other pristine runs ==
DF-5510 Ta: PRINTER(0) wrong 4/4; Tb: MODEM(1) from OOB bytes 4/4; Tc control UNKNOWN 4/4
DF-5511 wrong-captures per 50M iters: 2,1,1,6
DF-5512/DF-5513 reproduced 4/4