On Tue, 29 Jun 2010, Manjunath Doddavenkatappa wrote: > > Dear all, > > We have a sensor device with a USB connector (device's name is > TelosB in case if your aware of it). We use USB active cables to connect > such devices to a Linux PC (2.6.22-14-generic). Length of these active > cables range from 5 to 25 meters. Problem is while long 25 meter active > cables are used for connection. Communication with a device connected via > such a long cable is fine most of the time, but connection would go down > at least once/twice a day (although the corresponding /dev/ttyUSBX is > visible). Each time the connection is lost, removal and insertion of the > USB kernel module "ehci-hcd" will make the connection alright again > (modprobe -vr ehci-hcd; modprobe -v ehci-hcd). > > Is there any way to fix this without having to remove and insert the > module every time. I am new to USB framework on Linux. Like Felipe says, this is almost certainly a hardware problem caused by your active cables interacting poorly with the host controller. However... If you are still interested in a way to solve the problem without unloading and reloading ehci-hcd, there is a simple answer: Unplug and replug the cable. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
