questions on i2c-isa

Mark Studebaker mds4 at
Sun Jan 4 21:33:17 CET 2004

It looks like when i2c-viapro is loaded, then via686a won't register.
Maybe a PCI registration conflict?

Jean Delvare wrote:
>>For all i2c accesses you need an i2c bus address 0x00 - 0x7f.
>>This concept doesn't work for isa busses.
> Oh yeah I must be stupid. This is why there is isadump for them.
>>>2* Is i2c-isa broken in 2.6? The sensors-detect script says I should
>>>use i2c-isa + via686a. I load both and have nothing in sensors. It
>>>is with 2.6.1-rc1. It used to work with 2.4.x + i2c-2.8.x.
>>I reported a while back that via686a sometimes worked and sometimes
>>didn't. Playing with rmmoding and modprobing the modules (in various
>>combinations, including i2c-isa and i2c-core), seemed to make a
>>difference, but I couldn't figure out what made it work or not and
>>never got to the bottom of it.
> I made a few tests on my A7V133-C, where there are two sensor chips:
> via686a on i2c-isa and as99127f on i2c-viapro. This is with linux
> 2.6.1-rc1.
> It turns out that whichever driver is loaded second will not detect
> anything. If I load via686a first, it works and no as99127f is detected.
> If I load w83781d first, no via686a is detected. And it's only a matter
> of chip drivers. The order in which bus drivers are loaded doesn't
> matter.
> Can you reproduce something similar on your side?
> This would tend to demonstrate that the problem doesn't necessarily come
> from the via686a driver.
> Thanks.

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