Comment 17 for bug 405120

I also tried booting with:

acpi_osi= [Yes, it ends at the equal sign.]
acpi_osi="Linux"
acpi_osi="!Linux" [I think this is the default but for the sake of completeness.]

None of it worked.

I disassembled the dsdt and found pearls like these:

                    Method (_BQC, 0, NotSerialized)
                    {
                        If (IGDS)
                        {
                            Return (BRTL)
                        }
                        Else
                        {
                            If (LAnd (LEqual (SPSG, One), LEqual (DPMD, One))) {}
                            Else
                            {
                            }
                        }
                    }