[openib-general] [ANNOUNCE] tvflash: userspace-only Mellanox HCA flash tool

[Grant Grundler]

On Tue, Sep 14, 2004 at 03:01:45PM -0700, Roland Dreier wrote:
>     Tom> ib_mthca 0000:81:00.0: Warning: couldn't set 64-bit PCI DMA mask.
>     Tom> ib_mthca 0000:81:00.0: Warning: couldn't set 64-bit consistent PCI DMA mask.
> 
> Hmm, I wonder what's up with that.  Does sparc64 limit PCI addresses
> to the low 4G or something?

It depends on the IOMMU support which is chipset specific.
AFAIK, sparc64/alpha/parisc platforms only support 32-bit DMA and force
everything through an IOMMU.

> Probably the kernel isn't mapping RAM to DMA addresses in the range
> 0...(high_memory - PAGE_OFFSET) (ib_mad_register_memory() kind of
> implicitly assumes this).

This is a broken assumption. The DMA support can return *anything*.
chipsets can use addresses > physical RAM present in the system
(assuming < 4GB RAM).

> I know how to fix this properly, it just requires a couple small API
> extensions.

cool.

grant