Problem with understanding DMA on some machines (known solution!), specs needed?

[Rafał Miłecki]

W dniu 25 lipca 2011 23:54 użytkownik Rafał Miłecki <zajec5 at gmail.com> napisał:
> Now, the question: when for real we should use such a solution?
>
> Larry, could you check your driver? Can you see anything about this?
> Is this maybe PCI (not PCIe!) specific?

I've checked thread "Interesting 14e4:4321". It seems both: 14e4:4321
and 14e4:4322 are using PCI slot and both are not working in DMA mode.
I start believing it's PCI specific.

If you take a look at current ssb code and defines:
> if (ssb_read32(dev, SSB_TMSHIGH) & SSB_TMSHIGH_DMA64)
> 	return SSB_PCIE_DMA_H32;
> else
> 	return SSB_PCI_DMA;
You can see 0x80000000 (SSB_PCIE_DMA_H32) has actually "PCIE" in it's
name. This can be true that 0x80000000 is *only* for *64-bit DMA* on
*PCIe*.

-- 
Rafał