I've a Dell XPS 13 L321x running Debian Jessie that cannot resume after being suspended. Hibernate works fine if you trigger it with
rmmod on the
mei_me drivers suggested in https://bugzilla.kernel.org/show_bug.cgi?id=86241 but no effect. I've similarly tried
rmmod on the various wifi drivers linked to
iwlwifi since https://askubuntu.com/questions/638835/xps-13-9343-failure-to-resume-from-suspend explained similar issues in much more recent XPS 13s, but again no effect.
I should probably actually blacklist these modules, or perhaps remove the wifi card itself. I could try using a 4.3 kernel too.
How can I actually diagnose the problem with resume though? Are there any ways to log the resume operation the way that suspend is logged?
I've found better information on suspend at https://wiki.ubuntu.com/UnderstandingSuspend and technique for debugging resume at https://wiki.ubuntu.com/DebuggingKernelSuspend although it does not work on my current kernel.
After playing around with single user mode suspend I feel confident the system simply does not detect the lid open event or key press events when suspended. And hibernate works because initially it's powering-on like normal. I suspect Linux is simply being too aggressive with the hardware that it deactivates when doing suspend. Any thoughts?