I found a workaround for the problem. Enabling the "USB S3 Wake-Up" BIOS option seems to fix this problem. I had it turned off since I bought the machine, but I guess something was introduced in 3.9 that triggers the issue. Judging from the amount of ACPI related issues on Samsung laptops, a true solution for the problem would be to never install Linux on them.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1223851 Title: High CPU load after resuming on Samsung NP550P5C in BIOS mode To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1223851/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs