[Linaro-mm-sig] [PATCH v4 0/2] Add p2p via dmabuf to habanalabs

Daniel Vetter daniel at ffwll.ch
Tue Jul 6 12:23:42 UTC 2021

On Tue, Jul 06, 2021 at 02:21:10PM +0200, Christoph Hellwig wrote:
> On Tue, Jul 06, 2021 at 10:40:37AM +0200, Daniel Vetter wrote:
> > > Greg, I hope this will be good enough for you to merge this code.
> > 
> > So we're officially going to use dri-devel for technical details review
> > and then Greg for merging so we don't have to deal with other merge
> > criteria dri-devel folks have?
> > 
> > I don't expect anything less by now, but it does make the original claim
> > that drivers/misc will not step all over accelerators folks a complete
> > farce under the totally-not-a-gpu banner.
> > 
> > This essentially means that for any other accelerator stack that doesn't
> > fit the dri-devel merge criteria, even if it's acting like a gpu and uses
> > other gpu driver stuff, you can just send it to Greg and it's good to go.
> > 
> > There's quite a lot of these floating around actually (and many do have
> > semi-open runtimes, like habanalabs have now too, just not open enough to
> > be actually useful). It's going to be absolutely lovely having to explain
> > to these companies in background chats why habanalabs gets away with their
> > stack and they don't.
> FYI, I fully agree with Daniel here.  Habanlabs needs to open up their
> runtime if they want to push any additional feature in the kernel.
> The current situation is not sustainable.

Before anyone replies: The runtime is open, the compiler is still closed.
This has become the new default for accel driver submissions, I think
mostly because all the interesting bits for non-3d accelerators are in the
accel ISA, and no longer in the runtime. So vendors are fairly happy to
throw in the runtime as a freebie.

It's still incomplete, and it's still useless if you want to actually hack
on the driver stack.
Daniel Vetter
Software Engineer, Intel Corporation

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