[Mesa-dev] [PATCH 0/3] GBM modifier plumbing

[Daniel Stone]

Hey Kristian,

On 13 March 2017 at 17:31, Kristian H. Kristensen <krh at bitplanet.net> wrote:
> Jason Ekstrand <jason at jlekstrand.net> writes:
>> I was talking to Daniel today and I think we also need another some sort of
>> GL or GBM api that gives you the modifiers supported for
>> rendering/texturing.  One option would be a gbm_get_modifiers_for_use()
>> entrypoint that takes a usage and gives you a set of modifiers that's
>> guaranteed to work for that usage.  For scanout, it would return LINEAR, X,
>> and Y on SKL+ and LINEAR and X on BDW-; it wouldn't return CCS because that
>> only works on a limited number of planes.  I say this now because we may
>> want to do that with the same DRI version bump as the rest of it.
>
> Are you aware of
>
> https://www.khronos.org/registry/EGL/extensions/EXT/EGL_EXT_image_dma_buf_import_modifiers.txt
>
> If you talked to Daniel, he probably brought it up - what's missing?

I guess it depends on how much asymmetry there is between texture and
render formats ... if there isn't much, then we could focus on landing
Varad's work and use that as a jumping-off point. I was under the
impression that there was a pretty big difference for some hardware,
though I guess the GBM implementation would still rank by optimality
when allocating ...

Cheers,
Daniel