Help - Search - Members - Calendar
Full Version: Usb & Networking
Linuxhelp > Support > Technical Support
Joey
I've run into a weird problem and can't find any information about it. Perhaps someone on the forums has run into this before..

I'm running Red Hat Linux 9 and whenever I connect my USB camera (HP 318) to the system my networking goes dead (the camera works fine under linux though). In order to get the networking back up I have to run 'ifdown eth0', 'ifconfig eth0 <ip>' and then 'route add default gw <ip> metric 1'

Any ideas why this keeps happening?

Thanks
hughesjr
Is the network device a USB device ... if not, the only thing I can think of is a possible IRQ conflict between the network card and the USB controller. I didn't find anything specific about that on the web though.
Joey
The camera is USB and connects to my USB hub which connects to the USB port in the back of the computer. The network card is PCI. I'll have to check the irq's and stuff next time i use the camera.
ctrunk514
Is it just the camera; can you have other devices plugged into the USB hub without this problem?
Joey
It's the only USB device I have that plugs into the hub. my mouse plugs into the back of the pc directly.
ctrunk514
I wonder what would happen if you plugged the mouse into the hub, would you have the same problem?

Maybe try taking the HUB out of the loop by plugging the camera directly into the a USB port on the PC.


I know that these suggestions seem like workarounds, but sometime in finding a workaround we uncover the true issue.
Joey
I unplugged the USB hub and plugged the camera directly to the back of the system and the connection came down again. It's probably an IRQ issue.
Joey
Okay, I was playing around with the camera just now and it happened again.

When I plug the camera into the computer to unload it etc, the network is still up. The moment I disconnect the camera / power it off, the networking dies and I have to run ifdown eth0, ifup eth0.

I checked the interrupts and they are not conflicting with each other. This is totally boggling my mind.
hughesjr
Looking a little more into this, it seems to be a hotplug / pci bus issue. I can't find an exact match, but there are hotplug (usb, pcmcia) issues with the PCI bus in several kernel versions ... and they are very specific to things like Motherboard chipset type and the kernel version installed.

Are you using a pre-compiled redhat kernel package or did you compile your own kernel?
Joey
preinstalled default redhat kernel.
This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.
Invision Power Board © 2001-2017 Invision Power Services, Inc.