[LinuxBIOS] question about Config.lb
Ben Hewson
ben at hewson-venieri.com
Tue May 29 23:37:23 CEST 2007
ron minnich wrote:
> On 5/29/07, Ben Hewson <ben at hewson-venieri.com> wrote:
>>
>> there are the following 2 lines (115-116)
>> // Set ACPI base address to IO 0x4000
>> pci_write_config16(dev, 0x88, 0x0401);
>
> so is it setting it to 401? or ...
>
> what's the chip do? This might actually be setting it to 4000 ...
>
> ron
>
well it is strange. the code further on accesses the power management
registers from 0x400. both the vt8231 & vt8235 set the bottom bit, don't
ask me why, or if it is consistant with other chipsets.
from the 8235 datasheet
Offset 8B-88 – Power Management I/O Base .................RW
31-16 Reserved ........................................ always reads 0
15-7 Power Management I/O Register Base Address
Port Address for the base of the 128-byte Power
Management I/O Register block, corresponding to
AD[15:7]. See “Power Management I/O Space
Registers” in this document for definitions of the
registers in the Power Management I/O Register
Block
6-0 0000001b
if it wasn't for the code further down that uses outw() from 0x400
onwards I wouldn't have commented on it.
anyway I will declare an extern for the base io as that is how it is
done in at least one of the AMD based examples.
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