Hi, I think I've discovered a bug in the kernel 3.16. The issue is related to the suspend/resume brightness with i965 integrated video controller. I discovered the bug was not present in the previous debian stable kernel 3.2 and is still present in the 4.2 and 4.3 kernel from backports. I compiled my own 4.4 kernel and now all seems to work. I also opened a bug request here:
https://bugzilla.kernel.org/show_bug.cgi?id=111621 Hope it can be useful to fix the bug in the current kernel of Jessie. Ricca