On Wed, Feb 25, 2009 at 10:52:57AM +0000, Peter Targett wrote: > Hi, > > Has anyone got any tips to track down a problem where some usb > devices "magically" appear to be unplugged, then re-appear > moments later and are restarted > correctly by my libusb daemon/server task. > > My setup is linux 2.6.9 (RHEL4.5) and libusb 0.1.12. Both of those are _very_ old. So it's going to be a bit hard for anyone in the community to offer you support. As you are using RHEL, have you tried contacting your vendor for support? You are paying for it :) > The USB devices are simply USB 1.1 devices using the Intel 8051 > device. In the past the same devices were used on a Windows PC and > worked fine. The reason for moving it to Linux was to merge control > of these devices with the underlying software that uses them. > > I have tried very recent versions of the Linux kernel, namely 2.6.27, > but couldn't see any improvement - part of the problem is > that the problem seemingly happens randomly. I am in the process > of rewriting the libusb part of the daemon/server task to > use the recent re-write of libusb, namely, libusb-1.0. Odds are it is a power issue, try providing more power to the devices with a external-power hub, or fix the cables to be ones that don't have shorts in them :) Please note that Linux can't control when devices "disappear", that is an electrical thing that it has no control over. good luck, greg k-h -- 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
