[RFC PATCH v2 1/3] drivers/accel: define kconfig and register a new major

[Oded Gabbay]

On Mon, Nov 7, 2022 at 3:10 PM Jason Gunthorpe <jgg at nvidia.com> wrote:
>
> On Mon, Nov 07, 2022 at 03:01:08PM +0200, Oded Gabbay wrote:
> > I don't agree with your statement that it should be "a layer over top of DRM".
> > Anything on top of DRM is a device driver.
> > Accel is not a device driver, it is a new type of drm minor / drm driver.
>
> Yeah, I still think this is not the right way, you are getting almost
> nothing from DRM and making everything more complicated in the
> process.
>
> > The only alternative imo to that is to abandon the idea of reusing
> > drm, and just make an independant accel core code.
>
> Not quite really, layer it properly and librarize parts of DRM into
> things accel can re-use so they are not intimately tied to the DRM
> struct device notion.
>
> IMHO this is much better, because accel has very little need of DRM to
> manage a struct device/cdev in the first place.
>
> Jason
I'm not following. How can an accel device be a new type of drm_minor,
if it doesn't have access to all its functions and members ?
How will accel device leverage, for example, the GEM code without
being a drm_minor ?

Librarizing parts of DRM sounds nice in theory but the reality is that
everything there is interconnected, all the structures are
interdependent.
I would have to re-write the entire DRM library to make such a thing
work. I don't think this was the intention.

The current design makes the accel device an integral part of drm,
with very minimal code duplication and without re-writing DRM.

Oded