compositor-wayland: ignore frame callback's time

Graphics / Wayland / Weston - Pekka Paalanen [collabora.co.uk] - 7 April 2015 03:27 UTC

Weston running the Wayland backend is nested. The parent compositor uses an unknown clock for the frame callback timestamps. This is quite likely a different clock from what the nested Weston chose as its presentation clock.

This means we cannot reasonably read the presentation clock and assume it has any relation to the timestamp got from the frame callback. In fact, this was seen to cause absurd repaint delays, trigger the insanity check, reduce fraterate, etc. problems, because we assume we can read the clock and compute the remaining repaint delay.

As we can't use the timestamp, ignore it, and read our own presentation clock instead.

The X11 backend does not suffer from this, because there the parent window system never provides us any timestamps, so we always read our own clock.

04f8a9b compositor-wayland: ignore frame callback's time
src/compositor-wayland.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

Upstream: cgit.freedesktop.org

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