Missing Thunderbolt 3 PCI-E atomics support

[Mika Westerberg]

On Wed, Mar 13, 2019 at 07:09:26PM +0100, Timur Kristóf wrote:
> Hi,

Hi,

> I was sent here by Greg KH from the Linux USB mailing list, I hope this
> is the right place to ask.
> 
> PCI-E atomics don't work for me with Thunderbolt 3.
> I see the following message from my Thunderbolt 3 eGPU in dmesg:
> 
> kfd: skipped device 1002:67df, PCI rejects atomics
> 
> Hardware is a Dell XPS 13 9370 (with i7-8550U CPU) connected to a Zotac
> AMP mini, with an AMD RX 570 graphics card. Due to this, I cannot use
> the GPU for OpenCL, because the compute stack requires PCI-E atomics
> support [1].
> 
> What could be the problem? Is this a hardware limitation or a missing
> feature in the Linux TB driver?

I don't think it has anything to do with TBT itself. AtomicOps is a PCIe
feature.

What does 'sudo lspci -vv' show for the ports in question?