[RFC dri3proto 01/16] Add modifier/multi-plane requests, bump to v1.1

[Adam Jackson]

On Mon, 2017-06-19 at 13:35 +0100, Daniel Stone wrote:
> On 13 June 2017 at 21:43, Adam Jackson <ajax at nwnk.net> wrote:
> > On Thu, 2017-06-08 at 19:43 +0100, Daniel Stone wrote:
> > > 
> > > +typedef struct {
> > > +    [...]
> > > +    CARD32  stride0 B32;
> > > +    CARD32  offset0 B32;
> > > +    CARD32  stride1 B32;
> > > +    CARD32  offset1 B32;
> > > +    CARD32  stride2 B32;
> > > +    CARD32  offset2 B32;
> > > +    CARD32  stride3 B32;
> > > +    CARD32  offset3 B32;
> > > +    [...]
> > > +} xDRI3PixmapFromBuffersReq;
> > > +#define sz_xDRI3PixmapFromBuffersReq 64
> > 
> > Why exactly four strides/offsets?
> 
> Because that's what KMS takes for AddFB2, and (not coincidentally)
> what EGL_EXT_image_dma_buf_import_modifiers also defines tokens for. I
> don't even know of anyone using four, which would be tri-planar Y/U/V
> with an auxiliary plane. But seemed prudent to line up with the
> external APIs.

Aux plane for alpha or transparency key maybe? But thanks, that
clarifies the intent for me. I wasn't sure whether the multiple buffers
were for front/back and left/right for stereo or something. If they're
for planar color then 4 is plenty unless someone wants like CMYKA or
something silly like that.

- ajax