Re: Suspend/hibernate not working on Dell XPS 15 9500 laptop

[Trevor Bentley <trevor@xxxxxxxxxx>]

> I don't suppose you have a serial port on this laptop? I ask because
> the serial log (and the possibility to issue debug keys) are about
> the only thing debugging-wise that may help here, short of someone
> noticing the underlying problem by code inspection.
Afraid not, it's hyper-modern; just 3 USB-C ports.

It looks like identical hardware in the Dell Precision 5550 model, in 
case anybody gets access to either and wants to test.
> Do you have any indication of the laptop at least partly waking up
> again, e.g. from some LED or other indicator activity?
None at all, no.  Could be missing the keyboard events entirely, or 
getting them and failing to wake.  I've tried built-in keyboard, 
external keyboard, and closing/opening the lid.
When using the /sys/power/pm_test commands, does that actually do 
anything in a Xen environment, or is that being consumed by dom0 and not 
triggering the real VMM low-power paths?  Is there any similar debug 
mechanism for the hypervisor?
Let me know if there is any useful information I can extract.  I'm happy 
to build patched kernels if it will help.
Thanks,

-Trevor