Hi Bjorn,
On Mon, Jul 10, 2017 at 11:53:58AM -0500, Bjorn Helgaas wrote:
> I'm still confused. Per Samuel
> (6dd9dbac-9b65-bc7c-bb08-413a05d09...@sieb.net):
>
> Samuel> The other patch seems to fix this issue without disabling ATS.
> Samuel> Isn't that better?
>
> and Alex
> (bn6pr12mb1652df4130fc792b71dd9974f7...@bn6pr12mb1652.namprd12.prod.outlook.com):
>
> Alex> I talked to our validation team and ATS was validated on Stoney,
> Alex> so this patch is just working around something else. The other
> Alex> patch fixes it and is a valid optimization ...
>
> I'm confused about what this "other patch" is and whether we want that
> one, this one, or both.
The other patches floating around lowered the ATS flush-rate from the
AMD IOMMU driver, which makes the issue disappear as well. But the issue
only disappeared, it is not solved and could probably still be
reproduced with a GPU usage pattern that increases the ATS flush-rate.
So blacklisting the device for ATS is still the safest thing we could do
here.
Regards,
Joerg
