# How do I ID devices on SMBus



## tomdean (Dec 2, 2011)

How do I id devices on the SMBus?


```
> uname -a
FreeBSD Envy.tddhome 8.2-STABLE FreeBSD 8.2-STABLE #3: \
 Mon Oct 24 11:38:59 PDT 2011 \
 tomdean@Envy.tddhome:/usr/obj/usr/src/sys/GENERIC  amd64
> dmesg | grep ^CPU:
CPU: Intel(R) Core(TM) i7-2820QM CPU @ 2.30GHz (2294.80-MHz K8-class CPU)
> kldstat
Id Refs Address            Size     Name
 1   21 0xffffffff80100000 dd2040   kernel
 2    2 0xffffffff80ed3000 75890    sound.ko
 3    1 0xffffffff80f49000 25088    snd_hda.ko
 4    1 0xffffffff80f6f000 27f8     coretemp.ko
 5    4 0xffffffff81012000 897      smbus.ko
 6    1 0xffffffff81013000 1020     iicsmb.ko
 7    1 0xffffffff81015000 1305     iicbus.ko
 8    1 0xffffffff81017000 c6c      smb.ko
 9    1 0xffffffff81018000 2127     ichsmb.ko
> sudo smbmsg -p
Probing for devices on /dev/smb0:
Device @0x10: w
Device @0x60: rw
Device @0x64: rw
Device @0x88: rw
Device @0xa0: rw
Device @0xa4: rw
Device @0xc0: rw
```

tomdean


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## Terry_Kennedy (Dec 3, 2011)

tomdean said:
			
		

> How do I id devices on the SMBus?
> 
> 
> ```
> ...


It is [hardware] implementation-specific. The best thing would be to see if your motherboard manufacturer can provide this info, since things like fan speed divisors, voltage and temperature offsets, etc. can't be detected.

If your motherboard manufacturer can't/won't provide this info, you could see if you can locate a Linux live CD with the lm-sensors package installed. It provides a utility named sensors-detect.

Randomly poking devices to see how they respond can lock up the system, which is why there's a separate manually-initiated command in the lm-sensors package for doing this. It is unlikely you're going to permanently damage anything, but it may require a power cycle to get things back. While I was researching this reply, I probed one of my systems with smbmsg and received 45 alarm messages, and the remote web / IPMI interface became completely unresponsive, requiring a FreeBSD shutdown, followed by disconnecting the power cords for 30 seconds - long enough for the BMC processor to lose power and shut down.


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