i2c-0 device not created

Bug #39407 reported by Andras Mantia
16
Affects Status Importance Assigned to Milestone
Baltix
Invalid
Medium
Unassigned
Ubuntu
Expired
Medium
Unassigned

Bug Description

After a clean install (i686, via686a motherboard), sensors-detect complains that
"No i2c device files found. Use prog/mkdev/mkdev.sh to create them"

After creating the /dev/i2c-0 with "mknod /dev/i2c-0 c 89 0", it works.
I think this should be automatically created (by udev?).

"sensors" seem to work in both cases.

Note: the original reporter indicated the bug was in package 'lm-sensors'; however, that package was not published in Baltix.

Revision history for this message
Andras Mantia (amantia) wrote :

It's a bug in Kubuntu Dapper Flight 6, not Baltix...

Revision history for this message
Bazon (bazonbloch) wrote :

Not only Kubuntu, Ubuntu in general...
...alternative way to handle it:
The way it was done in warty:
http://ubuntuforums.org/showthread.php?t=2780

Anyway, it would be nice if this get fixed....(as we are on warty +3 ;-) )

Revision history for this message
Credomane (credomane) wrote :

I've had this problem but all I had to do was add "i2c_dev" to /etc/modules

Then all you have to do is either reboot or do a quick "sudo modprobe i2c_dev" and problem is gone.

Revision history for this message
Dirk (ubuntu-tobit) wrote :

And the real reason is that things are not done in the correct order in the sensors-detect script:-

 sensors-detect
# sensors-detect revision 1.393 (2005/08/30 18:51:18)

<snip>

It is generally safe and recommended to accept the default answers to all
questions, unless you know what you're doing.

 We can start with probing for (PCI) I2C or SMBus adapters.
 You do not need any special privileges for this.
 Do you want to probe now? (YES/no):
Probing for PCI bus adapters...
Use driver `i2c-nforce2' for device 00:01.1: nVidia Corporation nForce3 250Gb SMBus (MCP)
Probe succesfully concluded.

We will now try to load each adapter module in turn.
Module `i2c-nforce2' already loaded.
If you have undetectable or unsupported adapters, you can have them
scanned by manually loading the modules before running this script.

 To continue, we need module `i2c-dev' to be loaded.
 If it is built-in into your kernel, you can safely skip this.
i2c-dev is already loaded.

 We are now going to do the adapter probings. Some adapters may hang halfway

<snip>

 You will note that it tries to load i2c-dev *AFTER* trying to detect the i2c-nvidia and this is probably why loading it manually first works.

Revision history for this message
Credomane (credomane) wrote :

That's way different from what happens to me. I get this:

<snip>
root@mypc:~# sensors-detect
No i2c device files found. Use prog/mkdev/mkdev.sh to create them.
root@mypc:~# modprobe i2c-dev
root@mypc:~# sensors-detect
</snip>

After manually loading i2c-dev, running sensors-detect looks like what you posted.

Revision history for this message
gcc (chris+ubuntu-qwirx) wrote :

Hi,

I have this problem on Dapper and modprobe i2c-dev doesn't help. No device files are created in /dev:

chris@fen-apps(dev)$ ls /dev/i2c-*
ls: /dev/i2c-*: No such file or directory

chris@fen-apps(dev)$ sudo rmmod i2c-dev

chris@fen-apps(dev)$ sudo modprobe i2c-dev

chris@fen-apps(dev)$ sudo tail -1 /var/log/messages
Feb 26 14:46:43 fen-apps kernel: [44059888.540000] i2c /dev entries driver

chris@fen-apps(dev)$ ls /dev/i2c-*
ls: /dev/i2c-*: No such file or directory

chris@fen-apps(dev)$ sudo sensors-detect
No i2c device files found. Use prog/mkdev/mkdev.sh to create them.

If I manually create the device node with "mknod /dev/i2c-0 c 89 0" then it works, but I don't think I ought to do that or should need to do it on a udev system. I don't understand why "modprobe i2c-dev" doesn't do it.

Cheers, Chris.

Revision history for this message
Phillip Susi (psusi) wrote :

udev seems to be taking care of this these days, is anyone still having this problem?

Changed in ubuntu:
status: Confirmed → Incomplete
Revision history for this message
Launchpad Janitor (janitor) wrote :

[Expired for Ubuntu because there has been no activity for 60 days.]

Changed in ubuntu:
status: Incomplete → Expired
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