Re: [PATCH] pci: print out DMA mask info

[Grant Grundler <grundler@parisc-linux.org>]

On Fri, Oct 10, 2008 at 04:32:07PM +0900, FUJITA Tomonori wrote:
...
> > > Well, that's because I wrote gart's alloc_coherent and introduced
> > > dma_alloc_coherent_mask. ;)
> > 
> > oh. it is in tip
> 
> Yeah, it's in tip. But the current gart code uses coherent_dma_mask
> properly (GART in tip works in the same way as the current
> GART). IIRC, other X86 hardware IOMMUs (VT-d, Calgary, AMD) uses
> dma_mask in dma_alloc_coherent (AMD in tip uses coherent_dma_mask).

This is a bug. Care to submit a patch to fix it?
I don't have any of the docs or HW (VT-d, Calgary) to test it.


> > then can we remove consistent_dma_mask? just use dma_mask instead for all.
> 
> I don't think we can. One architecture needs it. The above usb
> chip seems to need it.

As noted before, several PCI-X devices support 64-bit DMA for payload
data but only 32-bit DMA for control data.

thanks,
grant