External DMA to gpu

[Dirk Eibach]

Hi Pekka,

> that would not involve Weston in any special way at all. Buffer
> allocation is usually done in the client any way the client wants. To
> ensure the buffer can be used by the compositor before you fill it with
> data, you would export your buffer as a dmabuf and use
> zwp_linux_dmabuf_v1 extension to send the buffer details to the Wayland
> compositor. If that succeeds, all is good and you can fill the buffer.
> After that, you have a wl_buffer you can attach to a wl_surface, and
> the compositor will just process it, even put it on a DRM plane
> bypassing compositing if possible.

Thank you so much, that is exactly the information I needed.
Is the  simple-dmabuf-v4l client an implementation of this principle?
So v4l2 offers an interface for passing the dmabuf. A v4l2 driver
would probably the right choice for my grabber anyway.

Cheers
Dirk