Having some flaky suspend/resume behavior on Ubuntu Mate 14.10:
With the screensaver and screen lock disabled, and with the screensaver removed as a startup application, the display does not wake from suspend. The machine wakes, and the keyboard backlight is illuminated, but the system is not responsive to keystrokes.
However, if I enable the screensaver as a startup app, but leave it and screen lock disabled, the display does wake correctly from suspend.
Is the screensaver a red herring?
I haven't seen this on 14.10 Unity or the other variants.
This is on a Lenovo ThinkCenter desktop using Intel Haswell video and a Dell 2410 monitor.
(Nothing in the logs looks unusual or flagged as an error.)