Well, after a bit more searching, I found that Award Bios uses "IPCA" to refer to ACPI. After enabling in BIOS, the ACPI is able to turn off the computer completely.
Hence only in APM mode the system halt does not function properly. Not a problem anymore thanks to ACPI. ** Changed in: ubuntu Status: New => Fix Released -- Ubuntu Gutsy does not turn off computer https://bugs.launchpad.net/bugs/182665 You received this bug notification because you are a member of Ubuntu Bugs, which is the bug contact for Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs