When running a fullscreen 3d app in 3-pipe mode (tested with openarena and nexuiz), all 3 pipes lose sync. When switching to console, the output is working. And when switching back to vt7, the screen graphical content is present for a fraction of time, and then loses sync as well. Nothing apparently suspicious in dmesg with drm.debug=0x04.
This one also works for me with ivb-3-pipe. However, depending on the mode configuration I chose in nexuiz, the second and third heads didn't come up, and the X display configuration got really confused. I was able to fix things again with the gnome display properties tool, and then ran nexuiz in 1280x1024 on 3 heads simultaneously (though not spread across heads, I don't think nexuiz supports that).
fixed in drm-intel-next
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