cvs commit: src/sys/dev/bce if_bcereg.h
gurney_j at resnet.uoregon.edu
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 bsdimp.com>
> : 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