drm_hwcomposer: Question about buffer importer

[Stefan Schake]

Hey Andrii,

On Tue, Mar 6, 2018 at 4:48 PM, Andrii Chepurnyi
<Andrii_Chepurnyi at epam.com> wrote:
>
> Could you please suggest me how to overcome that situation with buffers
> registration/deregistration?

I think drm_hwcomposer would be the wrong place to do any sort of caching.
There is a Gralloc usage flag for framebuffers. So I would suggest instead
that you do the heavy lifting that makes your AddFB2/RmFB slow already in
your Gralloc module upon framebuffer allocation. If you want, you could
probably just do the AddFB2/RmFB entirely in Gralloc and store the FB id
as part of the native handle.  This is what the Android-x86 drm_gralloc does:

https://github.com/robclark/drm_gralloc/blob/freedreno/gralloc.c#L236

Regards,
Stefan