FreeBSD 8.0 hangs on boot with ACPI enabled

John Baldwin jhb at
Thu Jan 7 22:54:44 UTC 2010

On Thursday 07 January 2010 2:16:24 pm Joerg Wunsch wrote:
> As John Baldwin wrote:
> > You can try disabling ACPI's thermal support 
> > (debug.acpi.disabled=thermal I think) to see if that helps.
> Yeah!  I've got FreeBSD 8 running for the first time with ACPI enabled
> on that machine now.
> So the question is why acpi_thermal hangs...  I might also try
> swapping the ahc0 controller back now.  Do you have any idea why this
> one gets a correct resource allocation with debug.acpi.disabled=sysres
> but not otherwise?  Is that rather a bug in the ACPI BIOS or in
> FreeBSD?
> I could probably live with enabling both debugging options for that
> machine, but I'd also like to help avoiding in particular the hard
> hang in acpi_thermal since it might perhaps also affect other users.
> Thanks a lot for all your help so far, John, it's really appreciated!

Wait, does disabling acpi_thermal change the system resource settings such at 
ahc now works even with sysres not disabled?  That is weird!  That has to be
some weird quirk in the BIOS.  As far as debugging the acpi_thermal hang I 
think you would want to add some printfs to the acpi_thermal kthreads to 
narrow down where the hang occurs.

John Baldwin

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