Present bufer fips in Xwayland GSOC 2017, landed in Xserver 1.20 - - PowerPoint PPT Presentation

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Oct 09, 2023 21 likes •112 views

Present bufer fips in Xwayland GSOC 2017, landed in Xserver 1.20 Roman Gilg 1 / 9 Problem statement T earing with Xwayland clients trying to use Present extension. Additional copy from Pixmap. 2 / 9 Solution overview Idea: fip

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Present bufer fips in Xwayland

GSOC 2017, landed in Xserver 1.20

Roman Gilg

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Problem statement

earing with Xwayland clients trying to use Present extension.

Additional copy from Pixmap.

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Solution overview

Idea: fip Pixmaps on separate wl_bufers.
New Present “mode“, does fips per window, not per screen:

– minimal change to old screen fip code, – also available on multi-monitor systems and in parallel, – complete notify event waits for second driver call.

Xwayland integration:

– listens for frame and release events, – timer fallback when no frame callbacks incoming.

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present/...

Window fip mode:

– fips per window, – waits for additional call from driver before telling client,

that it can reuse the Pixmap,

– switches parent Pixmap to fipped one (currently only

does fips if child window same rect as parent).

Split screen and window mode into sub routines via function

pointers, asks driver for support.

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hw/xwayland/...

Commits fipped Pixmaps as separate wl_bufers.
On bufer release event tells Present that the fip completed.
Aligns msc with frame callbacks (or a fallback timer).
Currently only fips if child window rectangle matches parent

window rectangle (might be possible with subsurfaces).

First come frst serve: frst child window only requesting fips

is allowed to do it.

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Bug squashing

Priv struct per Window, not only per xwl_window.
Remove fake crtc.
Fix freed pointer access.
Open bug: failed assert on Window reparent, patch by Olivier

Fourdan posted to mailing list yesterday.

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Future work

Present window mode on arbitrary child windows:

– In Prsent copy back to parent window Pixmap? – In Xwayland probably with subsurfaces.

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Thank you

Daniel Stone, GSOC mentor
Michel Dänzer, patch series review + feedback
Adam Jackson, testing + feedback
Olivier Fourdan, bug hunting
Lionel Landwerlin, bug hunting

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