With my 2011 MBP, when connected to my external screen I always encounter an issue when waking up from sleep mode, if the lid was closed (and only if lid is closed from what my tests show).
To summarize:
- MBP + External screen + Lid closed
Wake-up with scrambled external screen and black MBP screen. MBP frozen. - MBP + External screen + Lid not closed
Wake-up normally from sleep mode. - MBP without external screen (lid closed or not)
Wake-up normally from sleep mode.
Do you have any idea of what could cause this and how I could fix the issue?
Here is how my external screen looks like after a wake-up in the first case:

I've seen this issue but it's for older version of MBP and my system is up to date regarding the Software Update option.
Edit: Last EFI update installed yesterday seems to have fixed the issue!
