In my case the W520 always freezes after Grub and before reaching the login screen when Discrete Graphics is enabled in the BIOS.
I've tried BIOS version 1.06, 1.22 and the latest 1.25 (1.25 on the Lenovo website but 1.24 when flashed), with the same result. I've read https://wiki.ubuntu.com/DebuggingACPI and can confirm that acpi=off always works and acpi=ht never does. According to that page this means that "the issue is in the ACPI table parsing code itself, or perhaps the SMP code." -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/776999 Title: [Lenovo W520] laptop freezes on ACPI-related actions To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/776999/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
