[PATCH] unstable/drm-lease: DRM lease protocol support

[Simon Ser]

On Friday, June 28, 2019 12:58 PM, Pekka Paalanen <ppaalanen at gmail.com> wrote:
> On Fri, 28 Jun 2019 11:23:53 +0200
> Philipp Zabel p.zabel at pengutronix.de wrote:
>
> > On Thu, 2019-06-27 at 20:36 +0000, Simon Ser wrote:
> >
> > > What would be other use-cases for DRM leases? Probably fullscreen games?
> >
> > One use case I'd like would be presentation software, where tagging the
> > projector as non-desktop beforehand would avoid spilling the desktop
> > onto the presentation display upon connection, before the presentation
> > is started.
>
> Hi,
>
> I don't think that is a good idea. Presentation software (Libreoffice,
> web browsers, Evince, ...) probably does not want to grow a whole DRM
> KMS backend just to be able to drive a projector.

I totally agree.

> It would be much better for compositors to handle presentation outputs
> specially on their own to not extend the normal desktop contents there,
> and have a simple dedicated extension for presentation software to put
> a wl_surface on a presentation output (if necessary, maybe xdg_output
> and fullscreening to a specific wl_output is already enough).
>
> There are much more categories of outputs than just "desktop" and
> "non-desktop". I would avoid extending and confusing the meaning of
> "non-desktop" from what it currently is in the Linux kernel.
>
> Personally I am sceptical that even non-VR games would really benefit
> from DRM leases, because games might want to switch between windowed and
> fullscreen, users might want to see desktop notifications sometimes,
> etc. and again the DRM KMS backend is not easy to write.
>
> VR apps at least can rely on a VR runtime that knows how to drive DRM
> KMS properly, and there the use of DRM leases is well justified.

Yes. +1 to all of this.