Both drivers/gpu/drm/i915/intel_acpi.c and drivers/gpu/drm/nouveau/nouveau_acpi.c call _DSM methods with parameters of _DSM(Buffer, Integer, Integer, Integer). The ACPI spec defines the parameters to be _DSM(Buffer, Integer, Integer, Package). On a UL30VT, the AML preforms operations on Arg3 which are not valid for an Integer data type, resulting in ACPI faults. Excerpt of DSDT: Method (_DSM, 4, NotSerialized) { If (LEqual (Arg0, Buffer (0x10) { /* 0000 */ 0xA0, 0xA0, 0x95, 0x9D, 0x60, 0x00, 0x48, 0x4D, /* 0008 */ 0xB3, 0x4D, 0x7E, 0x5F, 0xEA, 0x12, 0x9F, 0xD4 })) { Store (Zero, Local0) Store (ShiftLeft (DerefOf (Index (Arg3, 0x03)), 0x18), Local0) Add (ShiftLeft (DerefOf (Index (Arg3, 0x02)), 0x10), Local0, Local0) Add (ShiftLeft (DerefOf (Index (Arg3, One)), 0x08), Local0, Local0) Add (ShiftLeft (DerefOf (Index (Arg3, Zero)), Zero), Local0, Local0) ... The Index operation is only valid on a Buffer, String, or Package, which is perfectly reasonable given the definition of the _DSM call.
Created attachment 86301 [details] pass correct ACPI arg to _DSM Sorry for the eternal delay in looking at this. Is this patch the right thing to do? I'm a complete ACPI-noob ...
Also I'll restrict this to intel-only, please file a separate bug for nouveau, thanks.
Fix merged to drm-intel-next-queued: commit 44a258c9fa89435d9ec2b6bcee6260b94bd11ebd Author: Peter Wu <lekensteyn@gmail.com> Date: Thu Aug 1 18:21:28 2013 +0200 i915: fix ACPI _DSM warning