kern/40440: cd0(piixide0:1:0): illegal request

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

>Number:         40440
>Category:       kern
>Synopsis:       cd0(piixide0:1:0): illegal request
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Jan 20 13:45:00 +0000 2009
>Originator:     Andreas Gustafsson
>Release:        NetBSD 5.99.5 (source date 2008.12.30.19.38.36)
>Organization:
>Environment:
System: NetBSD/i386 on qemu or Compaq Deskpro EN SFF PC
Architecture: i386
Machine: i386
>Description:

When installing a NetBSD-current snapshot, the error
"cd0(piixide0:1:0): illegal request" is reported.

If I boot a qemu virtual machine from install floppy images and then
attempt to install the sets from a CD image, the error occurs at the
time when sysinst mounts the CD, causing the following output:

  Status: Running
  Command: /sbin/mount -rt cd9660 /dev/cd0a /mnt2
  cd0(piixide0:1:0): illegal request, data = 00 00 00 00 20 00 00 00 00 00

If I boot a physical i386 machine from an install CD, a similar error
is reported but at an earlier stage, when the kernel mounts the CD as
the root file system.

As far as I can tell, there are no ill effects from the error apart
from the error message itself, but it should be investigated and if
deemed harmless, suppressed to avoid needlessly alarming or confusing
users.

Using an automated binary search, I have narrowed down the time when
the error appeared to the commits identified by

  cvs rdiff -D 2008.12.30.19.37.49 -D 2008.12.30.19.38.36

involving the files

  src/sys/dev/scsipi/cd.c
  src/sys/kern/subr_disk_mbr.c
  src/sys/sys/disklabel.h

>How-To-Repeat:

Build a NetBSD-current install CD and attempt to install from it.

>Fix: