DF-4653 interleaving model: puc_setup_intr (puc.c:691-692) vs puc_intr (puc.c:406-409)

A. kernel order, faithful 2-store window:    dispatches=140263   NULL-arg dispatches=2   <-- kernel: siointr(NULL) panic
B. kernel order, widened (yield between):    dispatches=49191    NULL-arg dispatches=36901   <-- kernel: siointr(NULL) panic
C. FIXED order (arg first), same widen :     dispatches=126664   NULL-arg dispatches=0

B>0 while C==0 proves the publication order is the defect.
=== guest hardware probe: any puc-matched comm card? ===
NO comm-class (0x07) PCI device - no puc card present: kernel manifestation hardware-gated