Super I/O info and tool links

[amtal]

Nice writeup and tool - here's some details and reference to additional tools from r/reverseengineering:

Based on an open source driver for other chips in the family, the port writes listed in the blog set registers 0xf0 = 0 and 0xf1 = 0 on logical device 0x12 via Super I/O. The 0x87 writes are Super I/O entry - it's interesting that sending it once works, since that's what flashrom does for the device it supports. Were lm-sensors and and the nct6775 drivers working around some obscure bug, or replicating vendor driver behavior? (Is Super I/O a standard, or a stack of turtles each backwards-compatible with the one below?)

The nct6775 fan/intrusion switch driver partially supports logical devices 0x0a, 0x0b, and 0xd, and lm-sensors focuses on 0x0b. The coreboot superiotool linked from Wikipedia can likely help in further exploration.

[nagisa]

I’m aware of superiotool, I’ve already figured out the purpose of all these port writes as well. Thanks for the cross-post though!

[amtal]

Awesome :)