EHCI Gadget Debug

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This page is about using embedded GNU/Linux devices in order to get the USB debug logs.



Download the patches that maintain TTY connected while debug target power-cycles or when host controller is reset.

Apply the patches from one of the v3.8- or v3.10-debug-gadget directories on your kernel build tree.


  • You need to be familiar with (cross) compiling your kernel.
  • (Cross) compile it as usual but during the configuration do the following:

Go into Device Drivers:

Device Drivers  --->

Then go into USB support:

[*] USB support  --->

Then go into USB Gadget Support:

<M>   USB Gadget Support  --->

Then enable the following option:

<M>     EHCI Debug Device Gadget

Then select the serial option:

        EHCI Debug Device mode (serial)  --->


Remove all usb gadget drivers such as g_ehter or g_mass_storage with rmmod then do:

modprobe g_dbgp

Finding the USB debug port

See EHCI Debug Port#Finding the USB debug port

Tested hardware

Brand and Device kernel used Target devices works?
Goldelico GTA04 A3 neil-plus kernel and branch (3.7) Lenovo X60 Yes
Buglabs's bug 2.0 bug20-2.6.35-linaro's master (2.6.35) Lenovo X60 Yes