the following patch was just integrated into master: commit 4733c647bc64cef86f03efd64a145e4da6fef123 Author: Mike Loptien mike.loptien@se-eng.com Date: Tue Mar 5 14:21:28 2013 -0700
Persimmon DSDT: Add secondary bus range to PCI0
Adding the 'WordBusNumber' macro to the PCI0 CRES ResourceTemplate in the Persimmon DSDT. This sets up the bus number for the PCI0 device and the secondary bus number in the CRS method. This change came in response to a 'dmesg' error which states: '[FIRMWARE BUG]: ACPI: no secondary bus range in _CRS'
By adding the 'WordBusNumber' macro, ACPI can set up a valid range for the PCIe downstream busses, thereby relieving the Linux kernel from "guessing" the valid range based off _BBN or assuming [0-0xFF]. The Linux kernel code that checks this bus range is in `drivers/acpi/pci_root.c`. PCI busses can have up to 256 secondary busses connected to them via a PCI-PCI bridge. However, these busses do not have to be sequentially numbered, so leaving out a section of the range (eg. allowing [0-0x7F]) will unnecessarily restrict the downstream busses.
This change will apply to other AMD mainboards and will be in a different commit.
Change-Id: I44f22bc03a0dcbcd2594d4291508826cc2146860 Signed-off-by: Mike Loptien mike.loptien@se-eng.com Reviewed-on: http://review.coreboot.org/2592 Tested-by: build bot (Jenkins) Reviewed-by: Martin Roth martin.roth@se-eng.com Reviewed-by: Marc Jones marc.jones@se-eng.com
Build-Tested: build bot (Jenkins) at Fri Mar 8 01:00:19 2013, giving +1 Reviewed-By: Marc Jones marc.jones@se-eng.com at Fri Mar 8 23:59:13 2013, giving +2 See http://review.coreboot.org/2592 for details.
-gerrit