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>
1 file changed