[lm-sensors] [PATCH] sensors-detect: Check for 1-register-only device (testers wanted)

achim achim at ag-web.biz
Fri May 9 19:31:44 CEST 2008

Am Freitag, den 09.05.2008, 19:05 +0200 schrieb Jean Delvare:
> > Afterward i tried it with only 0x4c excluded and the smbus chip still
> > works. With no exclusions lm75 detection hangs at 0x4c and afterwards i
> > only get XX's from dumps.
> By "hangs" you mean it takes several seconds, or does it really stop?
> Are you certain that it's the LM75 detection causing problem? We check
> for no less than 33 different devices at address 0x4c...
Client found at address 0x4c
Probing for `National Semiconductor LM75'...         
This is where it stops for a few seconds.
i2cdump 0 0x4c w hangs in a way that i must cancle it with Ctrl-C and
afterwards i need a reboot to get correct dumps.

> Anyway, most certainly the problem is with word transactions on this
> device you have at 0x4c. That won't be easy to work around, but I'll
> take a look anyway, maybe I'll have an idea. If I do, I'll ask you -
> again - to help with testing. 

As i noted in an other mail the interface can be accessed via the pci
registers F3x1E80 (address) and F3x1EC0 (data).
Bit 3 of pci register F3x1E40 indicates that this way of access is
possible if unset (0b). But those addresses can not be accessed
via /proc/bus/pci atm. 

> Thanks *a lot* for all the help you are
> providing in this respect.
Glad I can help. I was curious for a long time how this i2c/smbus stuff
works in detail, so that is a good situation to find out more about.

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