[alsa-devel] [PATCH] ALSA: hda - allow 40 bit DMA mask for NVidia devices

[Ard Biesheuvel]

On 18 October 2016 at 13:46, Mike Travis <travis at sgi.com> wrote:
>
> Have you tested this change on a system which has physical
> addressing > 40 bits to insure that addresses > 40 bits are
> not simply truncated to an incorrect (mod 40) address?

The device should never see addresses > 40 bits, given that the DMA
mask is set to 40 bits not 64.

> By not restricting the addresses to 32 bits you are not
> restricting the device to the DMA32 zone.
>
> This is what caused the original panic on UV systems.
>
> Btw, the newest nVidia GPUs have > 40 bits of DMA address bits.
>

Thanks,
Ard.