Hi,

On Mon, Jun 21, 2021 at 09:10:19AM +0200, Thomas Zimmermann wrote:
> Am 21.06.21 um 08:27 schrieb Tomohito Esaki:
> > Virtual DRM splits the overlay planes of a display controller into multiple
> > virtual devices to allow each plane to be accessed by each process.
> > 
> > This makes it possible to overlay images output from multiple processes on a
> > display. For example, one process displays the camera image without compositor
> > while another process overlays the UI.
> 
> I briefly looked over your patches. I didn't understand how this is
> different to the functionality of a compositor? Shouldn't this be solved in
> userspace?

I think there could be a bunch of use-cases for something that could
"steal" a plane without the compositor knowing.

Something I'd really like to work at some point for example is that the
downstream RaspberryPi display driver has a visual clue when it's
running too hot or is in over-current.

I don't think this is the right solution though. The DT binding makes it
far too static, and if there's a compositor I'd assume it would want to
know about it somehow (at least if it's from the userspace) ?

Maxime