Re: iwlwifi problem with iommu/intel-iommu: Enable CONFIG_DMA_DIRECT_OPS=y and clean up intel_{alloc,free}_coherent()

[Christoph Hellwig]

> By reverting this commit the card works again, tested in 4.17.3 . I've noticed 
> that the corresponding amd commit ( b468620f2a1dfdcfddfd6fa54367b8bcc1b51248)
> has been reverted in linus tree (e16c4790de39dc861b749674c2a9319507f6f64f), 
> and 4.16.X stable tree iirc,  but the intel one has not been reverted.
> 
> hw: Lenovo P50 Intel(R) Core(TM) i7-6820HQ CPU @ 2.70GHz
> 
> Please let me know if more details are needed, but CC: me as I'm not currently 
> subscribed to LKML.

It probablty is the same issue.  Did you check if you can just revert
the commit cleanly on top of current mainline and that fixes the issue
for you?