[PATCH 4/4] drm/doc: document front-buffer rendering

[Simon Ser]

On Thursday, July 13th, 2023 at 10:23, Pekka Paalanen <pekka.paalanen at collabora.com> wrote:

> > + * To perform front-buffer rendering, user-space should set FB_ID to the
> > + * previous framebuffer in atomic commits.
> > * CRTC_ID:
> > * Mode object ID of the &drm_crtc this plane should be connected to.
> > *
> 
> It's unclear to me what "previous framebuffer" means, although I know
> what you want to say. How about:
> 
> When a KMS client is front-buffer rendering, it should set FB_ID to
> the same front-buffer FB on each atomic commit. This implies to the
> driver that it needs to re-read the same FB again. Otherwise drivers
> who do not employ continuously repeated scanout cycles might not update
> the screen.

Thanks for the suggestion! Looks good to me, will send in v2.

> Btw. is it enough to set only FB_DAMAGE_CLIPS and not touch FB_ID?

Hm, I must admit I have no idea.