Shutdown and HMDI

Hi Everyone,

I've a pretty strange problem on my Ubuntu 15.10 desktop.

Sometimes when I shutdown my computer it stays blocked on the tty screen asking for logging (without being possible to write anything).

I finally found out that as soon as I plug a HDMI monitor to my computer it mess up shutdown, sleep or hibeate function. Even if I unplug the HDMI screen I caot shutdown or sleep/hibeate. If I close the lid the screen becomes black but the computer continues to run.

The only way I have is to press on/off button and then to force reboot. I can then tu off my computer normally. To summarize as soon as an HDMI is / has been plugged to the computer then things go wrong. Looks like HDMI stays on and then it blocks.

Hope you'll help me to find a solution,

Have a nive evening,

Florian