[RFC] Using DC in amdgpu for upcoming GPU

[Lukas Wunner]

On Tue, Dec 13, 2016 at 10:03:58AM -0500, Cheng, Tony wrote:
> On 12/13/2016 4:40 AM, Lukas Wunner wrote:
> > If the Linux community contributes to DC, I guess those contributions
> > can generally be assumed to be GPLv2 licensed.  Yet a future version
> > of the macOS driver would incorporate those contributions in the same
> > binary as their closed source OS-specific portion.
> 
> I am struggling with that these comminty contributions to DC would be.
> 
> Us AMD developer has access to HW docs and designer and we are still
> spending 50% of our time figuring out why our HW doesn't work right.
> I can't image community doing much of this heavy lifting.

True, but past experience with radeon/amdgpu is that the community has
use cases that AMD developers don't specifically cater to, e.g. due to
lack of the required hardware or resource constraints.

E.g. Mario Kleiner has contributed lots of patches for proper vsync
handling which are needed for his neuroscience software.  I've
contributed DDC switching support for MacBook Pros to radeon.
Your driver becomes more useful, you get more customers, everyone wins.


> > Do I understand DAL3.jpg correctly that the macOS driver builds on top
> > of DAL Core?  I'm asking because the graphics drivers shipping with
> > macOS as well as on Apple's EFI Firmware Volume are closed source.
> 
> macOS currently ship with their own driver.  I can't really comment on what
> macOS do without getting into trouble.

The Intel Israel folks working on Thunderbolt are similarly between
the rock that is the community's expectation of openness and the hard
place that is Apple's secrecy.  So I sympathize with your situation,
kudos for trying to do the right thing.


> I guess we can nak all changes and "rewrite" our
> own version of clean up patch community want to see?

I don't think that would be workable honestly.

One way out of this conundrum might be to use a permissive license such
as BSD for DC.  Then whenever you merge a community patch, in addition
to informing the contributor thereof, send them a boilerplate one-liner
that community contributions are assumed to be under the same license
and if the contributor disagrees they should send a short notice to
have their contribution removed.

But IANAL.

Best regards,

Lukas