6.0 BETA3 reboot hangs on SMP system if BIOS USB disabled

[John Baldwin]

On Tuesday 30 August 2005 05:07 pm, M. Warner Losh wrote:
> In message: <200508301623.57973.jhb at FreeBSD.org>
>
>             John Baldwin <jhb at freebsd.org> writes:
> : On Tuesday 30 August 2005 02:59 pm, M. Warner Losh wrote:
> : > In message: <200508301422.46354.jhb at FreeBSD.org>
> : >
> : >             John Baldwin <jhb at FreeBSD.org> writes:
> : > : On Monday 29 August 2005 08:51 pm, Mark Kirkwood wrote:
> : > : > John Baldwin wrote:
> : > : > > Ok, your BIOS is being a PITA. :)  First off, can you try setting
> : > : > > 'hw.pci.enable_io_modes=0' from the loader and seeing if that
> : > : > > fixes the problem?
> : > : >
> : > : > Sure does, thanks for looking at this!
> : > :
> : > : Ok, don't go away. :)  Warner or I can work on a patch to fix this
> : > : then that won't require you to set that tunable.
> : >
> : > I think that might be very hard to do that.
> : >
> : > While some (bogus) BIOSes set the maps to be all f's for devices they
> : > have disabled, many devices default to this value on power up.  Since
> : > we have to perform lazy resource assignment for these devices, it may
> : > be difficult to differentiate between the unassigned case and the
> : > disabled case.  Is there something I'm missing as to how we can tell
> : > the difference between these two cases?
> :
> : That should be identical cases.  The problem currently is that we think
> : that 0xffffffff is valid and we turn on the MEMEN bit in the PCI command
> : register, so when the box goes to reboot it tries to execute the BIOS
> : code that is normally mapped at 0xffff0000 and ends up executing what
> : that BAR maps instead, hence his hang.  Basically, I think we should
> : treat 0xffffffff just like we treat 0x0.
>
> We can treat 0xfffffxxxx the same as we treat '0' fairly easily enough
> in pci_add_map.  However, this is different than treating the device
> as being disabled.  What will likely happen is that we'll allocate
> fresh resources for the device, in effect re-enabling it.  If that's
> OK, then I'd agree that the fix is a one liner (well, more with
> comment updates).

Yes, that's ok.

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
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