Bug 75545

Summary:	Blitting a partial region to the front buffer produces corrupted display
Product:	Mesa	Reporter:	Federico Mena-Quintero <federico>
Component:	Other	Assignee:	mesa-dev
Status:	RESOLVED MOVED	QA Contact:
Severity:	normal
Priority:	medium
Version:	9.2
Hardware:	Other
OS:	All
Whiteboard:
i915 platform:		i915 features:

Description Federico Mena-Quintero 2014-02-26 20:49:26 UTC

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

Comment 1 GitLab Migration User 2019-09-18 20:17:23 UTC

-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/mesa/mesa/issues/904.

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.