recent USB MFCs cause panics

[Warner Losh]

From: Julian Elischer <julian at elischer.org>
> do you remember the full extent of your fix?
> I'm just learning about the bus/device stuff as I go..
> the trick is bringing forward as much of the USB code withoug bringing
> forward a bunch of subr_bus etc. as well.

I'm sure that cvs does:

revision 1.63
date: 2004/09/09 20:43:49;  author: imp;  state: Exp;  lines: +2 -34
We don't need a uhub_child_detached() routine now that we don't detach
device_t instances when no driver attaches.  They are left around, and
we need to remember them.

# The usbd_device_handle->subdevs[] array likely is completely bogus
# at this point, but one change at a time, since its removal will need
# to have similar code replace it extracted from newbus.

Part of the patch submitted by Peter Pentchev after an excellent
analysis of the underlying problems.

MFC After: 1 week

which lead me to the following from
CVSROOT/commitligs/sys.20040922.gz:

imp         2004-08-14 22:10:26 UTC

  FreeBSD src repository

  Modified files:
    sys/dev/usb          uhub.c usb_port.h usb_subr.c 
  Log:
  Next step in making usb more newbus:
  o reprobe children when a new driver is added to uhub
  o fix the usbd_probe_and_attach to set the ivars to a malloc'd area, as well
    as freeing the ivars on child destruction.
  o Don't delete children that don't attach. Evidentally, the need to do this
    is a common misconception.
  o minor formatting foo that may violate style(9) at the moment, but keeps the
    diffs against my p4 tree smaller.
  
  This does not solve the ugen gobbling things up problem, but the fixes
  I have for that expose bugs in other parts of the tree...
  
  Revision  Changes    Path
  1.61      +14 -26    src/sys/dev/usb/uhub.c
  1.66      +5 -1      src/sys/dev/usb/usb_port.h
  1.68      +31 -37    src/sys/dev/usb/usb_subr.c

imp         2004-09-09 20:43:49 UTC

  FreeBSD src repository

  Modified files:
    sys/dev/usb          uhub.c 
  Log:
  We don't need a uhub_child_detached() routine now that we don't detach
  device_t instances when no driver attaches.  They are left around, and
  we need to remember them.
  
  # The usbd_device_handle->subdevs[] array likely is completely bogus
  # at this point, but one change at a time, since its removal will need
  # to have similar code replace it extracted from newbus.
  
  Part of the patch submitted by Peter Pentchev after an excellent
  analysis of the underlying problems.
  
  MFC After: 1 week
  
  Revision  Changes    Path
  1.63      +2 -34     src/sys/dev/usb/uhub.c

imp         2004-09-09 20:47:28 UTC

  FreeBSD src repository

  Modified files:
    sys/dev/usb          usb_subr.c 
  Log:
  Add comments about why we're freeing subdevs (which is completely
  redundant at this point and should be retired).  Don't free subdevs if
  we don't attach any devices.  This was leaving stale device_t's
  around.  Don't touch the device if it isn't attached since the name
  isn't meaningful then.  Switch from strncpy (properly used) to
  strlcpy.
  
  From a patch submitted by Peter Pentchev
  
  Revision  Changes    Path
  1.70      +11 -8     src/sys/dev/usb/usb_subr.c


I can't recall of there were other commits to follow.

Warner