5.1beta2 on Alpha ES40 w/ 32GB pys ram

[Andrew Gallatin]

Bernd Walter writes:

 > 
 > You can see that the second hose has pci0 as well.

That should be fine..  they are in separate PCI address spaces.

 > Much worse a bridged card could get a bus number that is also used on
 > another hose and it fails obscurly within FreeBSD.

Having the same bus number appear on multiple bridges should also be
OK.  Again, the hose is its own address space.  

Are you worried about rman?

 > Currently I'm forced to keep bridged cards in the same hose.
 > 
 > This machine also doesn't initialize io space on bridges and some
 > drivers have problems with memory space.

That's bad.

 > And if we do it ourself than it might be reasonable to think about
 > hot-plug PCI some day.
 > 
 > I havn't followed that idea very much because I worried about what SRM
 > would do if we tamper with his configuration.
 > Your Linux example sounds promissing.

On miatas, linux shuffles pci memory mappings around so that it can
use a 2GB direct map.  This is great, except that linux does not halt
cleanly back to the SRM.  At shutdown time, it attempts to restore the
same settings it found, but when halting, all you get is a repeating
register dump.  FreeBSD, which doesn't do anything this fancy (and
which is limited to a 1GB direct map, due to the @#@#% stupid place
the SRM puts the PCI memory spaces), halts fine.   Perhaps we can make
it work right, but there are drawbacks.


Drew