Mike Loptien ([email protected]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/2684
-gerrit commit fe487f638d781307de91c21178d96634407f669e Author: Mike Loptien <[email protected]> Date: Tue Mar 12 10:21:24 2013 -0600 Persimmon DSDT: Add OSC method The _OSC method is used to tell the OS what capabilities it can take control over from the firmware. This method is described in chapter 6.2.9 of the ACPI spec v3.0. The method takes 4 inputs (UUID, Rev ID, Input Count, and Capabilities Buffer) and returns a Capabilites Buffer the same size as the input Buffer. This Buffer is generally 3 Dwords long consisting of an Errors Dword, a Supported Capabilities Dword, and a Control Dword. The OS will request control of certain capabilities and the firmware must grant or deny control of those features. We do not want to have control over anything so let the OS control as much as it can. The _OSC method is required for PCIe devices and dmesg checks for its existence and issues an error if it is not found. Before this change, dmesg gave this message: pci0000:00: Requesting ACPI _OSC control (0x1d) pci0000:00: ACPI _OSC request failed (AE_NOT_FOUND), returned control mask: 0x1d ACPI _OSC control for PCIe not granted, disabling ASPM After this change, dmesg looks like this: pci0000:00: Requesting ACPI _OSC control (0x1d) pci0000:00: ACPI _OSC control (0x1d) granted Change-Id: I1494285def7440972f0549b7cb73eb94dafc72c2 Signed-off-by: Mike Loptien <[email protected]> --- src/mainboard/amd/persimmon/dsdt.asl | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/src/mainboard/amd/persimmon/dsdt.asl b/src/mainboard/amd/persimmon/dsdt.asl index 148d7b0..d29bbff 100644 --- a/src/mainboard/amd/persimmon/dsdt.asl +++ b/src/mainboard/amd/persimmon/dsdt.asl @@ -1157,8 +1157,20 @@ DefinitionBlock ( Device(PCI0) { External (TOM1) External (TOM2) - Name(_HID, EISAID("PNP0A03")) + Name(_HID, EISAID("PNP0A08")) /* PCI Express Root Bridge */ + Name(_CID, EISAID("PNP0A03")) /* PCI Root Bridge */ Name(_ADR, 0x00180000) /* Dev# = BSP Dev#, Func# = 0 */ + + /* Operating System Capabilities Method */ + Method(_OSC, 4) + { /* Check for proper PCI/PCIe UUID */ + If(LEqual(Arg0,ToUUID("33DB4D5B-1FF7-401C-9657-7441C03DD766"))) + { + /* Let OS control everything */ + Return (Arg3) + } + } + Method(_BBN, 0) { /* Bus number = 0 */ Return(0) } -- coreboot mailing list: [email protected] http://www.coreboot.org/mailman/listinfo/coreboot
