[libhid-discuss] Unable to connect to USB device at the second run.

Peter Stuge peter at stuge.se
Fri Jan 22 14:35:40 UTC 2010

Johan Uiterwijk Winkel wrote:
> When the test programm is run for the second time most of the time
> we are unable to connect to the device.

This is almost exclusively caused by a bug in device firmware.

> Resetting the USB device using libusb also does not solve the
> problem.

It is not possible to reset a USB device from software. The closest
you can come is to manipulate the hub which the device is connected
to and make it tepmorarily remove power from the right port, but
there is no API for doing this.

IIRC the thread on the libusb list ended with the discovery that the
device firmware could not handle a configuration request when it was
already configured, but please do check the archive. I believe it was
discussed in the last three or four months.


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