[LinuxBIOS] s2881 fan control

[Stefan Reinauer]

* Ward Vandewege <ward at gnu.org> [060511 23:50]:
> > > 0000:01:04.3 Bridge: Advanced Micro Devices [AMD] AMD-8111 ACPI (rev 05)
> > > ...
> > > -40: 80 f1 00 04 00 00 00 00 20 14 50 00 00 00 00 00
> > > +40: 80 f1 00 07 00 00 00 00 20 14 50 00 00 00 00 00
> > 
> > Try the attached patch
> 
> That didn't help. 0x43 was still set to 04, and I could not set the fan
> speed. There was a bracket missing from the patch, btw.

Looking at the datasheet of the 8111 this was a blind shot in the wrong
direction.

The bits 0:2 in this register are:

PPSTATE. Previous power state. Read-only. This field holds the most
previous power state from which the system came into the FON state. This
field resides on the VDD_COREX plane. Here are the possible states:

PPSTATE Power state
0h Reserved
1h POS power on suspend
2h C2
3h C3
4h MOFF mechanical off
5h STR suspend to RAM
6h STD suspend to disk
7h SOFF soft off

So LinuxBIOS reports mechanical off while factory bios reports soft off.
Interesting.

But I found some stuff that is worth following. Fans are controlled by
the IO mapped power management registers (PMxx) of the 8111. They are
called System Management I/O Mapped Registers in the specs on pages 
218 et sqq.

The base of the PMxx registers can be read from DevB:3x58 (32bit)
bits 15:8. (ie. pmbase=pci_read_dword(acpi_dev, 0x58) & 0xff00;)
See the aruma acpi code for more information. 
Iirc PMbase is 0xDD00 per default. So PM12 would require inb/outb to
0xdd12.

Also, there's GPIOs connected with FAN control: (pg 244 et sqq)
GPIO9  PMC9 FANCON1 08h (FANCON1 output) 1Xb N/A
GPIO10 PMCA FANRPM  08h (FANRPM input)   1Xb direct

And on the SMBus you have the following registers:
Fan Control Register PMF8 (Sounds like this belongs to the PMxx
registers)

Ok, now we need to glue this all together so that it works.

Stefan


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