Curtaining API / Force blanking displays

[Daniel Stone]

Hi,

On Tue, 7 Apr 2020 at 09:23, Pekka Paalanen <ppaalanen at gmail.com> wrote:
> Maybe I should underline the read/write race:
>
> You do not get notified when a display server updates the screen, so
> you poll. When your poll returns a new FB id,

And that's only useful for Wayland systems. On X11, the server can
(and often does) render directly to a single static front buffer, so
whilst the observed KMS FB ID never changes, the content does. Which
you only know about if a) the display server tells you about it (so
the magic isn't all hidden in the kernel anyway), or b) you just
blindly update the content on a timer.

Cheers,
Daniel