disable 64-bit dma for one PCI slot only?

Mark McConnell markmc at dataabstractsolutions.com
Tue Jul 19 00:29:47 UTC 2011

On 18 Jul 2011 at 15:06, Scott Long wrote:
{Re: disable 64-bit dma for one PCI ...}:

> >> I would like to disable 64-bit addressing for the SATA card, but 
> >> permit it for the SCSI card.  Is this possible?
> > 
> > You'd have to hack the driver perhaps to only disable 64-bit DMA for certain 
> > PCI IDs.  It probably already does this?
> > 
> The driver already had a table for determining 64bit DMA
> based on the PCI ID.  I guess there's a mistake in the
> table for this particular card.  I think that changing
> the following line to remove the AMR_ID_DO_SG64 flag
> will fix the problem: 
>  {0x1000, 0x1960, AMR_ID_QUARTZ | AMR_ID_DO_SG64 | AMR_ID_PROBE_SIG},
> Actually, what's probably going on is that the driver is
> only looking at the vendor and device id's, and is
> ignoring the subvendor and subdevice id's that would
> give it a better clue on the exact hardware in use. 
> Fixing the driver to look at all 64bits of id info (and
> take into account wildcards where needed) would be a
> good project, if anyone is interested. 
> Btw, I *HATE* the "chip" and "card" identifiers used in
> pciconf.  Can we change it to emit the standard
> (sub)vendor/(sub)device terminology? 
> Scott

Thank you for the discussion, John and Scott.  I see 
where this change would be made, Scott, and I want to try 
it when I have an opportunity.


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