cvs commit: src/sys/dev/usb ehci_pci.c

John Baldwin jhb at
Wed Mar 12 20:57:18 UTC 2008

jhb         2008-03-12 20:57:17 UTC

  FreeBSD src repository

  Modified files:
    sys/dev/usb          ehci_pci.c 
  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
  Revision  Changes    Path
  1.30      +4 -1      src/sys/dev/usb/ehci_pci.c

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