Comment 19 for bug 1390807

Unfortunately, I was quite busy and didn't actually report the problem to upstream kernel yet... But here is an update hoping this may help someone who experiences the same problem to save some time

As I further noticed, freezes happend not only during resume but also sometimes due to inactivity display lock, or sometimes when I was just pressing the suspend menu item (before actually suspend happens). So I assumed something else might be going on other than the resume. Since my brightness didn't work either, my first focus went to it.

I noticed I have two independent modules that attempt to manage the brightness: intel_backlight and dell_backlight. I also noticed that echoing different values into /sys/class/backlight/dell_backlight had no effect, so I balcklisted dell_laptop module in /etc/modprobe.d/blacklist.conf, and after reboot can no longer reproduce my issue.
Hope this is it and I got to the source...

My understanding is dell_laptop module was conflicting and causing the actual freeze.