I have a nearly-identical freeze, leading me to believe that closing the lid isn't necessary.
My computer is set to have a screensaver after 15 minutes idle; then after another 15 minutes idle (ie 30 minutes total) to turn off the screen. At this point, the laptop may come back normally -- however after a long time (overnight) the screen stays off regardless of any input. I ALT+SysReq+REISUB to reboot.
I have a nearly-identical freeze, leading me to believe that closing the lid isn't necessary.
My computer is set to have a screensaver after 15 minutes idle; then after another 15 minutes idle (ie 30 minutes total) to turn off the screen. At this point, the laptop may come back normally -- however after a long time (overnight) the screen stays off regardless of any input. I ALT+SysReq+REISUB to reboot.