Since others in this bug may not have seen it and it would have saved me some Googling, the commit in http://lists.freedesktop.org/archives/intel-gfx/2010-May/006948.html seems to be the source of the problem. After reverting that commit, an otherwise vanilla 2.6.34 kernel works for me on an E6510 with the i915 driver.
Since others in this bug may not have seen it and it would have saved me some Googling, the commit in http:// lists.freedeskt op.org/ archives/ intel-gfx/ 2010-May/ 006948. html seems to be the source of the problem. After reverting that commit, an otherwise vanilla 2.6.34 kernel works for me on an E6510 with the i915 driver.