Intel i945: ACPI: Add _OSC method
Add the ACPI Operating System Capabilities Method and let the
operation system control everything.
Commit »AMD Fam14 DSDT: Add OSC method« (00a0e76b) [1] is used as
a template.
The Lenovo X60 [2] running the Parabola GNU/Linux distribution [3] is
used for testing.
Before that change:
$ dmesg | egrep -e OSC -e ASPM
[ 0.108036] pci_root PNP0A08:00: ACPI _OSC support notification failed, disabling PCIe ASPM
[ 0.108040] pci_root PNP0A08:00: Unable to request _OSC control (_OSC support mask: 0x08)
[ 0.118089] ACPI _OSC control for PCIe not granted, disabling ASPM
[ 16.874569] e1000e 0000:01:00.0: Disabling ASPM L0s L1
With that change:
$ dmesg | egrep -e OSC -e ASPM
[ 0.107962] pci_root PNP0A08:00: Requesting ACPI _OSC control (0x1d)
[ 0.108003] pci_root PNP0A08:00: ACPI _OSC control (0x1d) granted
[ 0.111052] pci 0000:01:00.0: disabling ASPM on pre-1.1 PCIe device. You can enable it with 'pcie_aspm=force'
[ 17.537970] e1000e 0000:01:00.0: Disabling ASPM L0s L1
[1] http://review.coreboot.org/2738
[2] http://www.coreboot.org/Lenovo_x60x
[3] https://parabolagnulinux.org/
Change-Id: I1caffa44eea447d553c01caaf431f2db241ea5ea
Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@no-log.org>
Signed-off-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-on: http://review.coreboot.org/2938
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
diff --git a/src/northbridge/intel/i945/acpi/i945.asl b/src/northbridge/intel/i945/acpi/i945.asl
index 47a6931..6a34b94 100644
--- a/src/northbridge/intel/i945/acpi/i945.asl
+++ b/src/northbridge/intel/i945/acpi/i945.asl
@@ -22,6 +22,25 @@
#include "hostbridge.asl"
#include "../i945.h"
+/* Operating System Capabilities Method */
+Method (_OSC, 4)
+{
+ // Create DWord-addressable fields from the Capabilities Buffer
+ CreateDWordField(Arg3, 0, CDW1)
+ CreateDWordField(Arg3, 4, CDW2)
+ CreateDWordField(Arg3, 8, CDW3)
+
+ /* Check for proper PCI/PCIe UUID */
+ If (LEqual(Arg0, ToUUID("33DB4D5B-1FF7-401C-9657-7441C03DD766")))
+ {
+ /* Let OS control everything */
+ Return(Arg3)
+ } Else {
+ Or(CDW1, 4, CDW1) // Unrecognized UUID, so set bit 2 to 1
+ Return(Arg3)
+ }
+}
+
/* PCI Device Resource Consumption */
Device (PDRC)
{