USB device not claimed by any active driver

Michael Scully agentscully at flexiblestrategies.com
Wed Jun 9 19:22:23 UTC 2004


Shanthi:

	You have to create the node manually.  Multitech sent me
instructions on this.  See below.

Mike Scully

<http://linuxusbguide.sourceforge.net/USB-guide-1.0.9/book1.html>, excerpt: 
You need to select the USB Modem (CDC ACM) support kernel option. If you
build as modules, you need to install the acm.o option.

You need to set up the device node entries for the various modems. You can
use up to 32 modems with this driver. Use the following commands to set up
the first four: 

mknod /dev/usb/ttyACM0 c 166 0 
mknod /dev/usb/ttyACM1 c 166 1 
mknod /dev/usb/ttyACM2 c 166 2 
mknod /dev/usb/ttyACM3 c 166 3 
You should now be able to use a terminal emulator program to attach to this
device and connect to your modem or other terminal device.

<http://www.linux-usb.org/> is the main source for Linux and USB. 

The following is an excerpt from
<http://www.signalground.com/article/3160886097>, 
If your current version of Linux has the ACM driver compiled into it, then
you're ready to roll. If it has the driver built as a module, then you'll
have to enable the driver with the following command:

modprobe acm

At this point, you may have to unplug the modem's USB cable and then plug it
back in (this isn't necessary if you're using kernel 2.4.X). You should see
the modem's lights come on. If you see some activity lights on the modem,
type the following:

lsmod

This command will display a list of loaded modules. The ACM module should be
displayed as loaded.

Now that you've got the driver loaded, you need to set up the device node
(in /dev) for the modem. You can use up to 32 modems with this driver, but
most people will only need to configure one. To set up a modem, use the
following command:

mknod /dev/usb/ttyACM0 c 166 0

You should now be able to use a terminal emulator program to attach to this
device and connect to your modem or other terminal device. Going one step
further, you can set up a symbolic link from /dev/modem to the ACM modem
device. This is accomplished by using the following command:

ln -s /dev/usb/ttyACM0 /dev/modem

That way, KPPP and friends can all refer to the modem as /dev/modem without
caring what type of modem it is.

KPPP Problems Under KDE 2
In doing our testing, we used a number of distributions ranging from Caldera
Open Linux 2.4 to Red Hat 6.2/7.0, but Mandrake 7.2 saw the most use.
Searching the net will produce a lot of queries about why KPPP and USB
modems don't seem to play together.

We observed that KPPP 2.0.1 (from KDE 2.0) hung while trying to set the
modem's volume before dialing. Trying all the typical KPPP configuration
tweaks (like changing CR/LF settings or init strings) didn't make matters
any better. We could use minicom to dial the modem or use manual scripts,
but KPPP refused to work.

Some users have speculated that there is a timing problem in KPPP in which
the commands aren't sent to the USB modem in a way that allows ample time
for responses. Whatever the reason, there is a subtle difference between how
a regular interal 56K modem handles KPPP and how a USB modem responds. This
behavior seems to affect a number of other USB modems.

We did find a patch to KPPP that allowed up to get further into the dialup,
connection and modem negotiations, but ultimately we ran into other problems
with PPPD dying unexpected (with error return code=4). In the end, the
current implementation of KPPP 2.0.1 seems to have a bug.

The old approach to initiating a PPP connection (buy dialing in minicom,
quitting without reset, and launching pppd) didn't work on this modem,
either. It seems that the ACM driver hangs up the modem as soon as the
handle is closed. In the end, the only way we could get this modem to dial
was to use pppd and chat. There may well be other dialers that'll handle a
USB modem with ease (we suspect that pon/poff will do it), but we didn't
have the time to be exhaustive. If we can figure out something that's easier
to set up, we'll be sure to post an update.





-----Original Message-----
From: redhat-list-bounces at redhat.com [mailto:redhat-list-bounces at redhat.com]
On Behalf Of Shanthi Paladugu
Sent: Wednesday, June 09, 2004 10:46 AM
To: redhat-list at redhat.com
Subject: USB device not claimed by any active driver

Hello,

  I have a machine with linux kernel 2.4.19 and when I
plug in a MultiTech USB modem, the device get
detected. I can see the messages in /var/log/messages
and also entries in the /proc/bus/usb/

However, the "acm.o" driver does not get loaded. I see
the message "USB device not claimed by any active
driver". The product and vendor id for the device are
6e0/0xf107. usbmodules --dev /proc/bus/usb/nnn/nnn
shows the output of "acm". 

My question is why isn't the acm driver getting loaded
when the device is detected. However everything works
fine if I insmod acm.o manually.

Any help will be appreciated.
Thanks,
Shanthi.



	
		
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