my Ubuntu does not suspend sometimes. Computer suspends several times correctly (2-3x) and then suddenly suspend process hangs with blinking cursor in upper left cornet and I can only reset the computer with reset button. I noticed this behaviour since upgrading from Ubuntu 13.10 to 14.04. I tried upgrading also from 14.04 to 14.10 (upgrade, not clean install) and the issue is still present. I use nvidia vga with proprietary drivers installed by "Additional Drivers" tool in Ubuntu.
Can anybody suggest how to diagnose this issue? What log should one look in for the suspend related messages?