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 [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
