I'm running 12.10 on my Thinkpad laptop with external screen connected through HDMI port.
Often, when the screen 'wakes up' from blank after period of inactivity I end up with lots of white dots flickering all over the screen. Plus it sometimes keeps turning on and off for no apparent reason.
What usually helps is switching off the external screen or (if I ran out of patience) pulling the cable out and plugging it back. Additionally, sometimes when I unplug the screen - laptop monitor doesn't 'wake up' either.
Could someone point me to the way of diagnosing the problem, and hopefully averting it? I'm running f.lux software - could that affect this behaviour?