USB shutdown issue

[valdis.kletnieks at vt.edu]

On Wed, 12 Apr 2017 09:49:38 +0900, manty kuma said:

> The source code that is doing this is here -
> http://androidxref.com/kernel_3.10/xref/drivers/usb/core/hub.c#4693

4693                            /*
4694				 * EM interference sometimes causes badly
4695				 * shielded USB devices to be shutdown by
4696				 * the hub, this hack enables them again.
4697				 * Works at least with mouse driver.
4698				 */

Seems self-explanatory enough.  Almost certainly not a software issue.

> But I did not get much info from here. Someone who is proficient with USB
> protocol might be able to asnwer this very quickly.

Most likely, you have a crappy/broken shield/ground connection somewhere
in the USB path.  Your device doesn't have a clean electrical connection
from it to the hub, and when the hub detects too much electrical noise on
the line, it dumps the device.
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