Bug 75545

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

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