On Wed, 21 May 2014, Mildred Ki'Lya wrote: > Hi, > > I have a problem with a USB device (4255:1000), running various kernels > from 3.12.6 (Fedora) up to 2.14.4 (ArchLinux). When I connect the > device, it appears all right. But after a few seconds of idle, it > disconnects itself. > > When I manage to use the device (read or write files to the mounted > filesystem) it stays connected. > > I published bug reports here: > https://bugzilla.kernel.org/show_bug.cgi?id=76511 > https://bugzilla.redhat.com/show_bug.cgi?id=1058194 > > The kernel log with kernel 3.14.4 shows a stack trace (bug report on > kernel.org) that didn't happen on earlier kernel version (3.12.6, Fedora > bug report). > > Note, usb autosuspend is off for that device: > > cat /sys/bus/usb/devices/1-6/power/control > on > > Do you have an idea what's wrong with this device. It works well on Mac > OS X and Windows. > > Thank you, > Please keep me to the Cc as I am not subscribed to the list. It's possible that the device can't handle Link Power Management. You can test this by writing 0 to the usb2_hardware_lpm file in the device's sysfs power directory: echo 0 >/sys/bus/usb/device/1-6/power/usb2_hardware_lpm 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
