Dear all, turns out, my system was suffering from completely different bug with similar symptoms. It was a problem with the motherboard BIOS. I upgraded the BIOS and the bug went away. I'm taking myself off the mailing list for this bug.
If you're suffering from a similar issue even after the fix in Xenial, try upgrading your BIOS. If that doesn't help and you're on a desktop, try clearing CMOS with the jumper (not through the menu) after the successful BIOS upgrade.
Dear all, turns out, my system was suffering from completely different bug with similar symptoms. It was a problem with the motherboard BIOS. I upgraded the BIOS and the bug went away. I'm taking myself off the mailing list for this bug.
If you're suffering from a similar issue even after the fix in Xenial, try upgrading your BIOS. If that doesn't help and you're on a desktop, try clearing CMOS with the jumper (not through the menu) after the successful BIOS upgrade.