SiS630 Disabling Embedded Devices (was: Software Watchdog Timer)

Alexander Amelkin spirit at
Tue Mar 18 14:34:01 CET 2003

Hello ollie,

This is the corrected version. The one I sent before contained an
error in the patch and wasn't sent to the list..

However, even without my patch I was getting the following error when I set

crt0.s:786: Error: Symbol write_lpc_register already defined.

As I discovered that was caused by the unneeded write_lpc_register
label in the Thus I modified my patch to remove that
line and now everything works fine.

Tuesday, March 18, 2003, 5:15:03 AM, you wrote:

ol> On Mon, 2003-03-17 at 21:35, Spirit wrote:

>> What I would really like to see somewhere in the LinuxBIOS code is the
>> options to disable SiS630 embedded modem and audio controllers. I
>> browser through the datasheet and didn't find how to disable them. I
>> probably should re-read it, but if anyone knows the way already, I'd
>> appreciate showing it to me.

ol> Search the keyword DISABLE_INTERNAL_DEVICE or something in the source. 
ol> Try writing different value (bit patterns) to the register 0x7c (not so
ol> sure ??) in southbridge. It is undocumented.

It's quite funny to hear about undocumented SiS chipset features from
a SiS person :)))

Anyway, thanks for the hint. That turned out to be a FAQ and the
answer can even be found on :)

I thought that with that information it would be nice to have
configuration options to enable and disable specific embedded devices,
so I wrote a small patch to sis/630/ I hope this will help
other people. Please find the patch file attached.

I tried the patch and it works. The board boots ok and the per-device
disable options work as supposed to.

Best regards,
 Spirit                            mailto:spirit at
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