Red Hat Bugzilla – Bug 626328
X.org: DBE should validate front and back buffers separately.
Last modified: 2013-01-10 22:13:14 EST
This bug has been copied from bug #596899 and has been proposed
to be backported to 5.5 z-stream (EUS).
2727481 build (RHEL-5.5-Z-candidate, /cvs/dist:rpms/xorg-x11-server/RHEL-5:xorg-x11-server-1_1_1-48_76_el5_5_2) completed successfully
setting verified field to nVidia as bug #596899 was verified (and this one is a clone)
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.
Technical note added. If any revisions are required, please edit the "Technical Notes" field
accordingly. All revisions will be proofread by the Engineering Content Services team.
The 'miDbePositionWindow' function allocates two pixmaps: a front buffer, and a back buffer. If the buffers are supposed to be initialized, it validates a graphic context (GC) against the front buffer, then uses it to fill and/or copy both the front buffer and the back buffer, without revalidating. If the acceleration architecture needed different GC functions for the two pixmaps, for example if allocation of the front buffer exhausted video memory, then this caused crashes because the GC was not validated for the back buffer pixmap. With this update, the crashes no longer occur and GC validation works as expected.