Per the comment immediately above yours, the resume after 24 hours occurs exactly the same on BIOS A04 as it does on A01. Since the problem did not occur on Saucy but does on Trusty, it may be a regression regardless of the BIOS version, hence wanting to test completely and thoroughly on A01 before upgrading.
Your requested information: dap-xps15:~$ sudo dmidecode -s bios-version && sudo dmidecode -s bios-release-date [sudo] password for dpoler: A04 03/28/2014 ** Changed in: linux (Ubuntu) Status: Incomplete => Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1318477 Title: [Dell XPS 15 9530] Wakes from sleep after exactly 24 hours + 3-5 seconds To manage notifications about this bug go to: https://bugs.launchpad.net/dell-sputnik/+bug/1318477/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs