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Date:   Tue, 6 Jul 2021 19:31:37 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Jason Gunthorpe <jgg@ziepe.ca>
Cc:     Daniel Vetter <daniel.vetter@ffwll.ch>,
        Oded Gabbay <oded.gabbay@gmail.com>,
        Oded Gabbay <ogabbay@kernel.org>,
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        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
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        Christian =?iso-8859-1?Q?K=F6nig?= <christian.koenig@amd.com>,
        Gal Pressman <galpress@amazon.com>, sleybo@amazon.com,
        Maling list - DRI developers 
        <dri-devel@lists.freedesktop.org>,
        linux-rdma <linux-rdma@vger.kernel.org>,
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        Dave Airlie <airlied@gmail.com>,
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        Leon Romanovsky <leonro@nvidia.com>,
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Subject: Re: [PATCH v4 0/2] Add p2p via dmabuf to habanalabs
Message-ID: <20210706173137.GA7840@lst.de>
References: <20210705130314.11519-1-ogabbay@kernel.org> <YOQXBWpo3whVjOyh@phenom.ffwll.local> <CAFCwf10_rTYL2Fy6tCRVAUCf4-6_TtcWCv5gEEkGnQ0KxqMUBg@mail.gmail.com> <CAKMK7uEAJZUHNLreBB839BZOfnTGNU4rCx-0k55+67Nbxtdx3A@mail.gmail.com> <20210706142357.GN4604@ziepe.ca> <CAKMK7uELNzwUe+hhVWRg=Pk5Wt_vOOX922H48Kd6dTyO2PeBbg@mail.gmail.com> <20210706152542.GP4604@ziepe.ca> <CAKMK7uH7Ar6+uAOU_Sj-mf89V9WCru+66CV5bO9h-WAAv7Mgdg@mail.gmail.com> <CAKMK7uGvO0h7iZ3vKGe8GouESkr79y1gP1JXbfV82sRiaT-d1A@mail.gmail.com> <20210706172828.GR4604@ziepe.ca>
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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.