Mike Loptien (mike.loptien@se-eng.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/2736
-gerrit
commit 6e5272af247e5b379a8b17c997c0a86605bcabb2 Author: Mike Loptien mike.loptien@se-eng.com Date: Fri Mar 15 11:11:12 2013 -0600
ASROCK Fam14 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 is the same change as made to Persimmon with change-id I44f22: http://review.coreboot.org/#/c/2592/
Change-Id: I5184df8deb7b5d2e15404d689c16c00493eb01aa Signed-off-by: Mike Loptien mike.loptien@se-eng.com --- src/mainboard/asrock/e350m1/dsdt.asl | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)
diff --git a/src/mainboard/asrock/e350m1/dsdt.asl b/src/mainboard/asrock/e350m1/dsdt.asl index bc45435..473092f 100644 --- a/src/mainboard/asrock/e350m1/dsdt.asl +++ b/src/mainboard/asrock/e350m1/dsdt.asl @@ -1477,6 +1477,22 @@ DefinitionBlock ( } /* end Ac97modem */
Name(CRES, ResourceTemplate() { + /* Set the Bus number and Secondary Bus number for the PCI0 device + * The Secondary bus range for PCI0 lets the system + * know what bus values are allowed on the downstream + * side of this PCI bus if there is a PCI-PCI bridge. + * PCI busses can have 256 secondary busses which + * range from [0-0xFF] but they do not need to be + * sequential. + */ + WordBusNumber (ResourceProducer, MinFixed, MaxFixed, PosDecode, + 0x0000, /* address granularity */ + 0x0000, /* range minimum */ + 0x00FF, /* range maximum */ + 0x0000, /* translation */ + 0x0100, /* length */ + ,, PSB0) /* ResourceSourceIndex, ResourceSource, DescriptorName */ + IO(Decode16, 0x0CF8, 0x0CF8, 1, 8)
WORDIO(ResourceProducer, MinFixed, MaxFixed, PosDecode, EntireRange,