Ubuntu 12.10 Black screen with mouse cursor sometimes after Ubuntu boot - nvidia optimus

Question

Possible Duplicate:
My computer boots to a black screen, what options do I have to fix it?

I have the problem on my ThinkPad T520 with Nvidia Optimus and SSD drive

Problem occurs with bumblebee installed and also without bumblebee, nvidia-current, bumblebee-nvidia packages. After reboot once or more it's ok.

In BIOS video is set to Optimus and "Detect by system" is disabled.

There are 3 cases when I can notice this behaviour:

1. When I start computer. Can't see login box, just mouse and black screen. Several reboot helps.
2. When my computer is waking on from suspending state.
3. When I use only external display and watching a movie. After 20 mins of inactivity external display is turning off. When I press any key no screen either.

It was working ok on my ubuntu 12.04 upgraded to 12.10.

I bought new SSD drive and installed fresh ubuntu 12.10 when the problem has started occuring.