Hi all,

On Tue, 9 Dec 2025 at 10:58, Nicolas Frattaroli
[off-list ref] wrote:

In either case, I think adhering to the atomic API to ensure
artifact-free presentation is more important here than enabling
a fast-path on RK3568. I do think in most real-world use case
scenarios, the fallback won't degrade user experience, because
almost everything performance intensive I can think of (video
playback, games) will likely already use a plane geometry
where the width is divisible by 4. 800, 1024, 1280, 1600, 1920,
2560, 3840 are all divisible by 4, so a window or full-screen
playback of common content won't need to fall back to GPU
compositing.

That's exactly it. Changing userspace's request may result in
unpleasant visual artifacts and other unwanted effects. If userspace
wants to always hit a fast path, then it will need some kind of
hardware awareness to do something different here. The patch series
pointed out gives userspace a good way to figure this out.

With my Weston maintainer hat on, I'd take a patch to
weston-simple-egl to allow it to use a different size with
command-line arguments if you'd like that for easier testing. (Fun
fact: it was specifically made 250x250 to discover issues such as
this, which wouldn't be uncovered by something that's aligned to a
generous power of two.)

Cheers,
Daniel