Graphics glitches

For the past days, I've seen a number of glitches on OS X Lion (update 10.7.3) with my mid-2010 Macbook Pro, and apparently, I'm not the only one.

It seems to happen especially on external monitors:
https://discussions.apple.com/message/17524501#17524501

However, iMacs have a lot more trouble:
https://discussions.apple.com/thread/3201871

A possible solution for the graphics glitches is mentioned at the end of the thread:
https://discussions.apple.com/message/17804906#17804906

White screen

UPDATE: this issue seems fixed with the 10.7.4 update

I've encountered a bug where the screen would blank, reproducible as follows:

With a closed laptop, hook up an external monitor (mini-DisplayPort) and keyboard
Press a key to wake screen, then I start working
At the end of day, I unplug keyboard and laptop
When coming home, open lid and click "switch user" (I have security settings such that it locks the display when closing the lid)
Look at white screen, where the mouse cursor is visible. Sometimes, after up to a minute, the screen will redraw correctly and show the login screen. Sometimes it'll just stay this way, and a hard reboot is required.

Black screen

I've also encountered a bug where the laptop screen would just stay black, not reproducible. I took the following steps:

With a closed laptop, hook up an external monitor and keyboard
Press a key to wake screen, then disconnect screen with the mini-DisplayPort
Open laptop lid, stare at black screen

Remotely I could log into the laptop, though.

Another set of circumstances happens as follows:

With a closed laptop, hook up an external monitor and keyboard
Go away until display sleeps
Come back and discover laptop cannot be woken up, but is still accessible via SSH

The following lines are then visible in the kernel.log:

 --- last message repeated 1 time ---
 kernel[0]: NVDA(OpenGL): Channel timeout!                                                
 --- last message repeated 1 time ---
 kernel[0]: NVDA(OpenGL): Channel timeout!
 --- last message repeated 1 time ---
 kernel[0]: NVDA(OpenGL): Channel exception!  exception type = 0xd = GR: SW Notify Error
 kernel[0]: NVDA(OpenGL): Channel timeout!
 kernel[0]: NVDA(OpenGL): Channel exception! exception type = 0xd = GR: SW Notify Error
 kernel[0]: NVDA(DisplayBase): Channel timeout!

UPDATE: this is still occurring with 10.7.4 update. Workaround is to keep the lid open