Re: [RFC] Updated plane support v3

[Marcus Lorentzon <marcus.xm.lorentzon@stericsson.com>]

On 06/20/2011 10:11 PM, Jesse Barnes wrote:
> This version adds both source and dest rect params to the set_plane
> ioctl, and makes the source fixed point to support hardware that needs
> it.
>
> I haven't changed the name of the SNB implementation yet (per Chris's
> suggestions) but will before it gets upstream.
>
> I'd be interested to see whether these interfaces will work for other
> hardware, so please take a close look at them and ideally implement them
> on your hardware to make sure (see my userspace example code from
> earlier posts if you want something to crib from).
>
> Thanks,
> Jesse
>
>    
Is it possible to position a plane above and below the "normal" crtc 
framebuffer? Plane z-order is unsigned, and I would assume 0 is default 
z-order.
Applications will need to position planes above and below crtc normal 
framebuffer. Below when using a translucent or color keyed framebuffer, 
and above if framebuffer is opaque.

So maybe add a one liner comment about z-order meaning and make it 
signed unless ordering should be solved in another way.

And should it be possible to only define planes with no crtc framebuffer 
at all? Use case, for example letter boxed video on black background 
with small UI controls/subtitles. In this case it's not power efficient 
to have a fullscreen fb with mostly if not all transparent pixels.

/BR
/Marcus