[ For l-k, the issue is that pci-pci bridges and the devices behind
  them are not initialized properly.  There are a number of Alphas
  whose built-in scsi controlers are behind such a bridge preventing
  these machines from booting at all.  Ivan provided an initial 
  patch to solve this issue.  ]

I've not gotten a chance to try this on the rawhide yet,
but I did give it a whirl on my up1000, which does have
an agp bridge that acts like a pci bridge.

Notable changes from your patch:

  * Use kmalloc, not vmalloc.  (ouch!)
  * Replace cropped found_vga detection code.
  * Handle bridges with empty I/O (or MEM) ranges.
  * Collect the proper width of the bus range.


r~