Re: [PATCH 2 of 13] ipath - set up 32-bit DMA mask if 64-bit setup fails

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



    Bryan> Some systems do not set up 64-bit maps on systems with 2GB
    Bryan> or less of memory installed, so we have to fall back to
    Bryan> trying a 32-bit setup.

Which systems does this happen on?

PowerPC with U3 or U4 northbridge, i.e. Maple or PowerMac G5 systems.
If the IOMMU (DART) is disabled, we have a 32-bit only DMA mask.  The
DART will be disabled by default if there is 2GB or less of memory (as
it isn't needed then).

I'm just curious, because mthca has

	err = pci_set_dma_mask(pdev, DMA_64BIT_MASK);
	if (err) {
dev_warn(&pdev->dev, "Warning: couldn't set 64-bit PCI DMA mask. \n");

and I've never had a single report of that warning triggering.

That's only because I never used those cards on systems with fewer
than 4GB of memory :-)


Segher

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux