Connecting USB modem to PC. Kernel rebuild required? How?

seabird505 · 05-28-2009, 03:26 AM

Hi!

I want to connect a GSM phone as a modem/com port to my PC using USB cable. When I plug in the USB cable to PC, Linux (Cent OS 5.2 - 2.6.18) don't detect it. Here are the log in /var/log/messages

Code:

May 28 04:55:20 MyPC kernel: usb 4-2: new full speed USB device using uhci_hcd and address 7
May 28 04:55:20 MyPC kernel: usb 4-2: configuration #1 chosen from 1 choice
May 28 04:55:20 MyPC kernel: drivers/usb/class/cdc-acm.c: Zero length descriptor references
May 28 04:55:20 MyPC kernel:
May 28 04:55:20 MyPC kernel: cdc_acm: probe of 4-2:1.1 failed with error -22

I googled for the error "kernel: drivers/usb/class/cdc-acm.c: Zero length descriptor references" and realized that a patch is required. However, I have never installed a patch or build a kernel before. Should I download the entire source code for my CentOS build, apply the patch and compile/install it again? CentOS website Wiki does not recommend recompiling the entire kernel as it will break the CentOS support. Please guide me what to do and how to do it.

Secondly, I will be using gnokii to communicate with my cell phone. Its config file dictates to use the port as /dev/ttyACM0. However I don't find any ttyACM0 file in /dev/ directory. Should I create a node for it like

mknod /etc/ttyACM0 c 166 0

Thanks for your time.

syg00 · 05-28-2009, 08:54 PM

Any reason for using Centos ?. That's a fork of RHEL - i.e. an enterprise Linux. As such it will never have support for the "latest-and-greatest" hardware.
If this is a personal PC, I'd suggest it would be easier to use a different distro (say Fedora in your case) that has more recent kernel (and thus hardware support) included.
If your modem is supported, the node will (should) be built automatically.
What model modem are you trying to use ?.