[LinuxBIOS] Asus smbus mux

koko citizenr at gmail.com
Sun Apr 1 22:58:22 CEST 2007

I started a thread (well, its me talking to myself) "read the spd on
A7V133" on lm-sensors list. My conclusions:

E:\dane\Testery !\sandra>SPDINFO.EXE 1 a7v
Ctrl 0, SMBus, Sys, IO 0000e800h, Mem 00000000h, Drv Intel PIIX4 SMBus
/ compatible, Brd A7V
Mux 0 Asus IO mux, IO 0000e44dh, Ext 4267320

rasz at capek:~$ cat /proc/ioports|grep e4
e400-e47f : motherboard
 e400-e403 : ACPI PM1a_EVT_BLK
 e404-e405 : ACPI PM1a_CNT_BLK
 e408-e40b : ACPI PM_TMR
 e410-e415 : ACPI CPU throttle
 e420-e423 : ACPI GPE0_BLK

I decompiled ACPI DSDT from my bios and found this :

   OperationRegion (\SGPO, SystemIO, 0xE44C, 0x04)
   Field (SGPO, ByteAcc, NoLock, Preserve)
       GPO0,   1,
               Offset (0x01),
       GPO8,   1,
           ,   2,
       GP11,   1,
               Offset (0x04)

1 Linux ACPI  - Bios ACPI mismatch,  0xE44C is not claimed and not
mapped properly
2 mux GPIO is mapped to 0xE44C-0xE44F.

We can reverse it by trial and error (or by talking to sandra/everest
developers, Im trying it now), or just use SPDINFO.EXE (its a part of
SiSoftware Sandra package) on board to board basis comparing data and
obtaining the right bit mask to switch smbus to SPD channel.

Im posting this because I saw some movement on VT82C686 front, and
this info will be needed to port to Asus boards (K7 ones hide SPD and
Clock chip).

Who logs in to gdm? Not I, said the duck.

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