This is not a serious problem, but I thought I would let developers know. I'm using amd64 Current, (8.99.26), and run the Xserver through the Xorg modular builds. I have noticed periodically that I get and error in my xconsole that reads:
kern error: [drm:(/usr/src/sys/external/bsd/drm2/dist/drm/i915/intel_sprite.c:132)intel_pipe_update_start] *ERROR* Potential atomic update failure on pipe A: -35
The processor is an Intel Core2 P8600 with Intel graphics, (G45). The error almost always happens when I'm using a brower like Firefox. There is no interruption of service, but I thought I'd let you know it's there, and has been there for a while in the 8.99.XX build.