Comment # 4 on bug 1022443 from Takashi Iwai

With the given acpi_osi option, basically BIOS reacts as if it were pre-Windows
7 OS.

Do you see the behavior on the system after the boot option?  For example, does
nouveau still work, or have you used only Intel graphics?

The likely reason of a lock up is the failure of GPU switching, either via
vga_switcheroo or runtime PM of nouveau.  In the former case, you'll lose the
whole graphics, so you might think it being a lockup although the system is
alive.

By booting with acpi_osi option, it behaves like Win-XP without the dynamic GPU
switching, and it avoids the lockup eventually on Linux, I suppose.