[Mesa-dev] [Bug 75545] New: Blitting a partial region to the front buffer produces corrupted display

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=75545

          Priority: medium
            Bug ID: 75545
          Assignee: mesa-dev at lists.freedesktop.org
           Summary: Blitting a partial region to the front buffer produces
                    corrupted display
          Severity: normal
    Classification: Unclassified
                OS: All
          Reporter: federico at gnome.org
          Hardware: Other
            Status: NEW
           Version: 9.2
         Component: Other
           Product: Mesa

For the original bug behind this, please see
https://bugzilla.gnome.org/show_bug.cgi?id=674208

In Gnome apps, including gnome-shell, Clutter and Cogl try to avoid doing a
full-screen update on every rendered frame by just doing a glBlitFramebuffer()
of the dirty region from the back buffer to the front buffer.  The idea is that
with software rendering, Mesa will do an XPutImage() of small regions, instead
of the whole screen, to minimize the amount of data transferred to the
(possibly remote) X server.  However, this is broken in drisw, and has been for
a couple of years now.

This piglit test exposes the bug (needs to be run with
LIBGL_ALWAYS_SOFTWARE=1):
http://lists.freedesktop.org/archives/piglit/2014-February/009701.html

-- 
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/mesa-dev/attachments/20140226/fee3f292/attachment-0001.html>