Unix Device Memory Allocation project

[Rob Clark]

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.

(Either way, the fourcc modifiers, and related EGL extension to query
modifiers, should be sufficient)

BR,
-R