John's Linux related stuff

ACPI Message LED for SiS630 Chipset

This is a hacked up driver which allows you to turn the Message LED on and off on a motherboard which uses the SiS630 chipset and has a Message LED.

I originally attempted to use ACPI to control the LED but that did not want to work so I disassembled the AML and worked out how it was meant to work.  That did not work either, seemingly because the ACPI was incorrect.

After an amount of stuffing around I managed to get the LED going.  The docs list the registers as read only but writing to them works so...


The driver was written for the Linux 2.4 kernel but is very small and could be ported to older kernels without much trouble.  It does not work with the 2.6 kernel but if someone wants to fix it I don't think it will be too hard.  Version 0.2 should build correctly for 2.4 with the included makefile.

The driver does not check to make sure that you have a SiS630 chipset so be warned.  You can check by doing

$ lspci

and looking for a line like this

00:01.0 ISA bridge: Silicon Integrated Systems [SiS] 85C503/5513

This is however the same ID as older SiS chipsets (5513).  I don't know what might happen if you use it on an older chipset.

This may also work on newer chipsets but if you do use ACPI then you might end up with some conflicts so be careful.

Last modified 20041109
Maintained by John Newbigin