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

[Kristian H. Kristensen]

Daniel Stone <daniel at fooishbar.org> writes:

> 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 ...

Right, but if it's more complicated than what
EGL_EXT_image_dma_buf_import_modifiers exposes, do really we want to
that logic into gbm?

Kristian