Hi Balbi and other USB developers. I am developing camera devices based on Xilinx ZynqMP, using the gadget framework and the build-in dwc3 core of the ZynqMP as USB3 controller and the build-in Cirrus SERDES as phy. Testing with a number of hosts and Windows 7, has shown sporadic reconnects when leaving U2/U1, caused by failing link training, where the host resets the bus. Sometime it also means it reconnect via USB2.
So to overcome this, I will like to have the option for disabling U1/U2 on the core when working with those hosts. Currently I have made a hack in ep0.c where I return EINVAL in dwc3_ep0_handle_u1 and dwc3_ep0_handle_u2 together with not setting DWC3_DCTL_ACCEPTU1ENA and DWC3_DCTL_ACCEPTU2ENA in dwc3_ep0_set_config Will though prefer a solution possible to upstream, so was thinking about adding two devicetree bindings. * snps,u1_disable_as_gadget: When set the core will not enable U1 if requested from host, nor initiate U1. * snps,u2_disable_as_gadget: When set the core will not enable U2 if requested from host, nor initiate U2. If you think this might be something which can be upstreamed I will prepare the code and send a patch for discussion. On the other hand, if you think that disabling U1/U2 via device tree as suggested should not be a feature no need for me to try making it a feature. Kind regards / Med venlig hilsen Claus Stovgaard Firmware Design Engineer Phase One
