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From:   Christoph Hellwig <hch@lst.de>
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Subject: Re: [PATCH v4 0/2] Add p2p via dmabuf to habanalabs
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On Tue, Jul 06, 2021 at 02:28:28PM -0300, Jason Gunthorpe wrote:
> > Also on your claim that drivers/gpu is a non-upstream disaster: I've
> > also learned that that for drivers/rdma there's the upstream driver,
> > and then there's the out-of-tree hackjob the vendor actually
> > supports.
> 
> In the enterprise world everyone has their out of tree backport
> drivers. It varies on the vendor how much deviation there is from the
> upstream driver and what commercial support relationship the vendor
> has with the enterprise distros.

I think he means the Mellanox OFED stack, which is a complete and utter
mess and which gets force fed by Mellanox/Nvidia on unsuspecting
customers.  I know many big HPC sites that ignore it, but a lot of
enterprise customers are dumb enought to deploy it.