Unix Device Memory Allocation project

[Daniel Vetter]

On Wed, Jan 04, 2017 at 08:06:24AM -0500, Rob Clark wrote:
> On Wed, Jan 4, 2017 at 7:03 AM, Daniel Stone <daniel at fooishbar.org> wrote:
> >> Speaking of compression for display, especially the separate
> >> compression buffer: That should be fully contained in the main DMABUF
> >> and described by the per-BO metadata. Some other drivers want to use a
> >> separate DMABUF for the compression buffer - while that may sound good
> >> in theory, it's not economical for the reason described above.
> >
> > 'Some other drivers want to use a separate DMABUF', or 'some other
> > hardware demands the data be separate'. Same with luma/chroma plane
> > separation. Anyway, it doesn't really matter unless you're sharing
> > render-compression formats across vendors, and AFBC is the only case
> > of that I know of currently.
> 
> 
> jfwiw, UBWC on newer snapdragons too.. seems like we can share these
> not just between gpu (render to and sample from) and display, but also
> v4l2 decoder/encoder (and maybe camera?)
> 
> I *think* we probably can treat the metadata buffers as a separate
> plane.. at least we can for render target and blit src/dst, but not
> 100% sure about sampling from a UBWC buffer.. that might force us to
> have them in a single buffer.

Conceptually treating them as two planes, and everywhere requiring that
they're allocated from the same BO are orthogonal things. At least that's
our plan with intel render compression last time I understood the current
state ;-)
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch