[i2c] asus_hides_smbus

Jean Delvare khali at linux-fr.org
Fri Nov 10 21:33:18 CET 2006

Hi Michael,

On Thu, 09 Nov 2006 01:58:07 +0100, Michael Müllner wrote:
> me run Suse 10.1 with there default Kernel:
> Linux dvb #1 Tue Sep 19 07:26:15 UTC 2006 i686 
> i686 i386 GNU/Linux
> and lm_sensors:
> sensors version 2.10.1 with libsensors version 2.10.1
> My Mainboard (P4B533-E) is on from this ASUS mobos where ASUS hide the 
> SMB bus.
> if me run:
> setpci -d 8086:24c0 f2.w=0061
> and than lspci -H 1 me see:
> 00:1f.3 SMBus: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) 
> SMBus Controller (rev 01)
> than mbmon works but sensors-detect still cant find anything :(
> I think its a problem with /proc/bus but i dont know how to add this 
> after boot.

No, /proc/bus is no longer used for i2c busses on 2.6 kernels.

> dmesg didnt display anything with "i801 SMBus" so i think this quirks.c 
> from this kernel is wrong or me need to activate something me didnt know.
> is there something me can try to get it running ?
> I realy hope someone can help me to get it running :)

The SMBus quirk was ruled unsafe when suspend support is enabled in the
kernel, so late 2.6.16 and later kernels disable the quirk when suspend
support (ACPI sleep states) is enabled. So if you want your SMBus back,
your choices are:

1* Ask Asus for a BIOS update where the SMBus is no longer hidden.
2* Recompile a kernel without suspend support.

Jean Delvare

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