cvs commit: src/sys/dev/bce if_bcereg.h

John-Mark Gurney gurney_j at
Wed Apr 26 17:12:21 UTC 2006

Warner Losh wrote this message on Wed, Apr 26, 2006 at 10:25 -0600:
> In message: <20060426.101245.90994186.imp at>
> : bus_size_t is for differences between two bus_addr_t quantities, since
> : it specifies the size of resources on a bus.  It is also used for
> : transfer sizes and the like.  That's why I think it should be a 64-bit
> : quantity: 64-bit - 64-bit = 64-bit.
> I should have added that if there's a substantial penalty for going to
> 64-bits, then we should avoid it.  My objections are based on the
> resource allocation perspective, not the DMA segment size perspective.
> It will be a while before video cards have > 4G window of resources
> presented to the system.  While an individual DMA transfer on the
> PCI-E bus may not cross such a boundary, I bleieve that individual
> resources can consume more than 4G.  Our PCI code doesn't handle BARs
> that are > 4G in size correctly, but it does handle BARs that are
> mapped anywhere in a 64-bit address space.

I have patches (in the sun4v tree) to the pcib code that has it
properly support 64bit addresses...  

  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."

More information about the cvs-src mailing list