Created attachment 27029 [details]
xorg conf file

mesa demo/isosurf got the similar issue,but the error is as below:
isosurf: intel_buffer_objects.c:103: intel_bufferobj_free: Assertion `!obj->Pointer' failed.
Aborted

I can't reproduce this here with Mesa 7.5.
I'm checking in some fixes for glxcontexts.c though.

Same issue here. I'm using version of
7.5.0~git20090622+mesa-7-5-branch.abfd56c2-0ubuntu0sarvatt
package. No 3D application working anymore, switching to High importance.

same issue happens in playing neverball game.

Ian, can you reproduce?

I'm increasing severity since it impacts real-world application.

the issue also impacts our glean case (texgen,vertattrib),I think it is a regression in mesa 7.5 branch. I am trying to bisect.

I find the reason, below commit caused this issue:
commit ff3da0966fc91cd5bcfed994e5edadbf25903c47
Author: Eric Anholt <eric@anholt.net>
Date:   Tue Jun 2 06:53:40 2009 -0700

	i915: Don't put VBOs in graphics memory unless required for an operation.

	This saves doing swtnl from uncached memory, which is painful.  Improves
	clutter test-text performance by 10% since it started using VBOs.
	(cherry picked from commit a945e203d4fe254593bc0c5c5d6caca45e65f9f7)

commit c72261f2a886e1f53025c2cf4b38b33ccfd62857
Author: Eric Anholt <eric@anholt.net>
Date:   Mon Jun 29 18:48:27 2009 -0700

    i915: Fix assertion failure on remapping a non-BO-backed VBO.
    
    Failure to set the obj->Pointer back to null tripped up the assertion.
    Bug #22428.
    (cherry picked from commit 57a06d3a48c9af1067ec05e3ad96c58f4b9b99be)

verified with below commits:
Libdrm:		(master)de1ed01214874dcdd6116ff2587c8710d6ed4d2d
Mesa:		(mesa_7_5_branch)4e43126a5915b1233c89c61400c8270d23d48ea3
Xserver:	(server-1.6-branch)a7a93c12f91e0de72868f17a555215f1795d9e2f
Xf86_video_intel:		(master)afac333bef4a0ac934f0e4d933dc5053d81ca88c
Kernel:       (qa-branch)07a2039b8eb0af4ff464efd3dfd95de5c02648c6