Everything was surprisingly smooth and easy. Thanks to BIOS and kernel upgrades, I didn't need to apply any patches to get suspend/restore working. I made the following adjustments:
1. Change BIOS sleep mode from Windows to Linux.
2. Remove the Thunderbolt 3 controller from the device list for the sys-usb Qube.
I did NOT enable BIOS support for Thunderbolt 3 as recommended in some other HCL reports; doing so fixed the lockup-on-wake issue, but at the cost of disabling all USB devices. Leaving this disabled and removing the thunderbolt controller from the sys-usb device list fixes the issue and doesn't seem to affect USB support at all, as far as I can tell.
The following peripherals are tested and functional:
- USB
- Keyboard, trackpad
- Built-in microphone
- Built-in camera
- Sound output
- Suspend and restore
I haven't yet tested HDMI output, but based on other reports don't anticipate trouble.