[PATCH 0/5] Improve Present support in Xwayland with per window flips

Michel Dänzer michel at daenzer.net
Wed Aug 30 02:42:38 UTC 2017

Hi Roman,

On 30/08/17 12:24 AM, Roman Gilg wrote:
> Originating from the bug report
> https://bugs.freedesktop.org/show_bug.cgi?id=99702
> and my own observations with Xwayland misbehaving when outscanning on overlay planes, this patch series aims at improving Present support in Xwayland.
> For that it introduces an internal flip mode API to Present, with that it's possible to try other Pixmap flips than just for a whole screen like before. For Xwayland we add a flip mode per window, but for example in the future we could also try to add a mode for flips per CRTC. Anyway the idea is to clearly separate different flip modes with their own code paths.
> In Xwayland we flip per window, and also with the last patch in the series use sub-surfaces for that in order to flip on child windows. In my tests this was still somewhat fragile.

I made some high level comments based on commit logs. I haven't reviewed
the patches in detail yet, because it seems difficult unless at least
some of them are split up:

* Moving code without any functional changes should be in its own patch,
  not intermixed with functional changes.
* Only one logical change per patch.

> * Mutter: Neverball framerate capped to 120 (probably Mutter doesn't release buffers faster)

Was that with PresentOptionAsync (e.g. via "V-Sync" disabled in the game
settings, or e.g. vblank_mode=0)? Without PresentOptionAsync, the
intention is for the presentation frame rate to match the scanout
refresh rate.

Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer

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