[Freedreno] [RFC PATCH v3 0/3] Support for Solid Fill Planes

[Simon Ser]

On Tuesday, January 31st, 2023 at 10:25, Pekka Paalanen <ppaalanen at gmail.com> wrote:

> indeed, what about simply using a 1x1 framebuffer for real? Why was that
> approach rejected?

Ideally we don't want to allocate any GPU memory for the solid-fill
stuff. And if we special-case 1x1 FB creation to not be backed by real
GPU memory then we hit several situations where user-space expects a
real FB but there isn't: for instance, GETFB2 converts from FB object
ID to GEM handles. Even if we make GETFB2 fail and accept that this
breaks user-space, then there is no way for user-space to recover the
FB color for flicker-free transitions and such.

This is all purely from a uAPI PoV, completely ignoring the potential
issues with the internal kernel abstractions which might not be suitable
for this either.