On Wed, 2017-05-24 at 10:44 +0200, Joerg Roedel wrote: > Hi Alexander, > > On Tue, May 23, 2017 at 07:54:12PM +0000, Deucher, Alexander wrote: > > > > I finally got an answer from the hw team and we validated ATS on > > stoney as well so in theory this patch shouldn’t actually be needed. > > I think we may actually be papering over some other issue. The > > following patch seems to also fix this issue (and other issues): > > https://www.spinics.net/lists/stable/msg172631.html > > Yeah, but it still looks to me like that the hardware got into some > weird state with the storm of ATS invalidations sent to it. > > The Completion-Wait loop timeouts seen in the original bug report > indicate that the IOMMU is waiting for a response that never comes. And > this is probably the ATS flush completion response from the GPU, as > disabling ATS on the GPU makes the issue disappear. The above patch doesn't actually fix any spec violation which could the GPU an *excuse* to crash and stop responding to invalidations, does it? It just seems to reduce the invalidation load a little, and thus paper over the problem that the card tends to crash under load. Absent a more coherent explanation, it still seems like the correct answer is to blacklist these devices for ATS because they're broken.
Attachment:
smime.p7s
Description: S/MIME cryptographic signature
