Bug 860611

I was executing the multihead test case on the nouveau driver, using 2012/09/25 testday LiveCD, on a notebook with GeForce Go 7300, playing with the notebook panel and an external VGA-connected LCD (http://www.smolts.org/client/show/pub_9d7fe254-01da-40af-ab77-93ed9260d8a4).

On various occasions, when disconnecting or repositioning the displays using the display configuration tool of Gnome, I experience freezing or blacking out of Xorg display. VT worked fine and HW cursor remained. Sometimes, Xorg would recover after some minutes.

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Example detailed description for one of the run
s:
* Correctly hot-connect the external LCD to the notebook.
* Enabled it, changed its position (left to the notebook display, right to it ...), move windows to it ... No problem.
(*) When I _disconnected_ it from the notebook, without having previously disabled it on Gnome display properties, the notebook screen went black, but cursor was available and moving. VT terminals were alive and usable.

Coming back and forth from the VT to the Xorg tty did not solve anything; Xorg display remained black. If I connected again the external LCD to the notebook, the LCD was recognized and correctly modeset, added to X, but it had the same black image on it, except for the HW cursor, which was also available on this display.

After approximately 2 minutes without, Xorg came back, apparently OK.
But I reconnected the external display to the VGA (operation that worked) and tried to execute a glxgears on the re-added second display. At the beginning the glxgears showed properly, but when I resized the glxgears window, the image on all displays _freezed_ and only the HW cursor moved correctly. I went back to the VT, which was working fine, and when returned to the X TTY, both displays were once more black + HW cursor.

Attached dmesg and Xorg log correspond to this situation.
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This display freezing problems are consistently reproducible on my notebook