kern/46547: umass: sd crashes when synchronizing cache while trying to suspend

[nathanialsloss%yahoo.com.au@localhost]

>Number:         46547
>Category:       kern
>Synopsis:       umass: sd crashes when synchronizing cache while trying to 
>suspend
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Jun 05 17:05:00 +0000 2012
>Originator:     Nat Sloss
>Release:        NetBSD Current 6.99.7
>Organization:
>Environment:
NetBSD beast 6.99.7 NetBSD 6.99.7 (LOCKDEBUG) #64: Tue Jun  5 17:42:52 EST 2012 
 build@beast:/usr/src/sys/arch/i386/compile/obj/LOCKDEBUG i386

>Description:
If booted up from a usb flash drive and then attempting to sleep (acpi state 3) 
the kernel crashes whilst trying to synchronize the cache.

The following was obtained from the crash:

Flushing disk caches done.
umass generic HBA error.
sd0 cache synchronization failed.

It then drops into ddb where I obtained the following back trace:

page fault type 6 code 0 eip 0 invalid address
0:
umass_bbb_state:0x193
usb_transfer_complete:0x18a
ehci_idone:0x131
softintr...

This problem has been bugging me for a while.  It did not occur in NetBSD 5.0.1.

The usb device still has power to it whilst this occurs (there is an indicator 
light).

I can shutdown ok, it just crashes while attempting to suspend.

>How-To-Repeat:
Boot up from an installation on a usb flash drive and try to suspend (acpi 
state 3).
>Fix: