kern/55461: ciss(4) no longer works

[gson%gson.org@localhost (Andreas Gustafsson)]

>Number:         55461
>Category:       kern
>Synopsis:       ciss(4) no longer works
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Jul 05 19:15:00 +0000 2020
>Originator:     Andreas Gustafsson
>Release:        NetBSD-current, source date >= 2020.07.04.14.49.24
>Organization:
>Environment:
System: NetBSD
Architecture: x86_64
Machine: amd64
>Description:

My amd64 bare metal testbed is hanging at boot since this commit:

  2020.07.04.14.49.24 jdolecek src/sys/dev/pci/ciss_pci.c 1.16

The last console messages printed before the hang are from the ciss
driver:

  [   1.1012041] pci0 at mainbus0 bus 0: configuration mode 1
  [   1.1012041] pchb0 at pci0 dev 0 function 0: Intel 5520 ESI Port (rev. 0x13)
  [   1.1012041] ppb0 at pci0 dev 1 function 0: Intel 5520/5500/X58 PCIe Root Port 1 (rev. 0x13)
  [   1.1012041] ppb0: PCI Express capability version 2 <Root Port of PCI-E Root Complex> x4 @ 5.0GT/s
  [   1.1012041] pci1 at ppb0 bus 5
  [   1.1012041] ciss0 at pci1 dev 0 function 0: HP Smart Array 11
  [   1.1012041] ciss0: interrupting at msix0 vec 0
  [   1.1012041] ciss0: 2 LDs, HW rev 2, FW 3.66/3.66, 64bit fifo rro
  [...]
  [  61.8400703] ciss0: workqueue busy: updates stopped
  [  92.3400561] ciss0: unqueued ccb 0xffff8b025e3d6c00 ready, state=0x10
  [ 152.4100278] ciss0: unqueued ccb 0xffff8b025e3d6a00 ready, state=0x10

This is running on a HP DL360 G7.  Full console log:

  http://www.gson.org/netbsd/bugs/build/amd64-baremetal/2020/2020.07.04.21.02.16/install.log

>How-To-Repeat:

>Fix: