K 10
svn:author
V 3
jhb
K 8
svn:date
V 27
2008-03-12T20:57:17.000000Z
K 7
svn:log
V 687
Relax the BIOS/OS sempahore handoff code to workaround different hard
hangs (one at boot, one at shutdown) in recent machines.  First, only try
to take ownership of the EHCI controller if the BIOS currently owns the
controller.  On a HP DL160 G5, the machine hangs when we try to take
ownership.  Second, don't bother trying to give up ownership of the
controller during shutdown.  It's not strictly required and a Dell DCS S29
hangs on shutdown after the config write.

Both of these changes match the behavior of the Linux EHCI driver.  I also
think both of these hangs are caused by bugs in the BIOS' SMM handler
causing it to get stuck in an infinite loop in SMM.

MFC after:	1 week

END