[Bug 79850] [awesomenauts][radeonsi] pageflip is clearly missing vblank with vsync on

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=79850

--- Comment #23 from Michel Dänzer <michel at daenzer.net> ---
(In reply to comment #21)
> It would mean the pixmap transformation is costing too much in time
> regarding vblank time, making happen the swap in the middle of the visible
> screen.

When the window pixmap is not the screen pixmap, a GLX/DRI2 buffer swap
involves two copies: one from the DRI2 back buffer to the window pixmap, and
one from the window pixmap to the screen pixmap. It's unrealistic for the
second copy to finish before the end of the vertical blank period, resulting in
the visible tearing.


(In reply to comment #22)
>  - I did swap my TAHITI XT (7970) with a JUNIPER PRO (5750), the pixmap
> transformation seems GPU bound since the tearing appears quite lower on
> JUNIPER PRO than with TAHITI XT.

Could be due to EXA vs. glamor. In the latter case, the copies described above
are rasterized as two triangles each, which makes the tearing more noticeable.

-- 
You are receiving this mail because:
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/dri-devel/attachments/20140702/dcfb2dce/attachment.html>