Hey Felipe, I've been tripping over an issue on my HiKey960 where with the usb-c gadget cable connected, the gadget code doesn't consistently seem to initialize properly. I had rarely seen this behavior previously, but more recently it has become more frequent and annoying. Usually, unplugging and replugging the USB-C cable would get things working again (but that's not helpful in test labs). I annotated a bunch of code trying to understand what was going on and I narrowed down the difference in the good and bad case to a dwc3 reset interrupts happening after usb_gadget_probe_driver() completes. In the good case, we see the reset interrupts, and in the failed case we don't. [ 16.491953] JDB: usb_gadget_probe_driver [ 16.495938] JDB: udc_bind_to_driver [ 16.499555] JDB: dwc3_gadget_start irq: 65 revision: 1429417994 [ 16.503803] JDB: __dwc3_gadget_ep_enable [ 16.507791] JDB: __dwc3_gadget_ep_enable [ 16.511715] JDB: dwc3_gadget_enable_irq [ 16.515582] JDB: usb_udc_connect_control [ 16.519510] JDB: usb_gadget_connect <in the bad case, this is all we see, the gadget device doesn't come up> [ 16.811010] JDB: dwc3_gadget_interrupt [ 16.814783] JDB: dwc3_gadget_reset_interrupt [ 16.819047] JDB: dwc3_reset_gadget [ 16.823935] JDB: dwc3_gadget_interrupt [ 16.827686] JDB: __dwc3_gadget_ep_enable [ 16.831611] JDB: __dwc3_gadget_ep_enable [ 16.994477] JDB: dwc3_gadget_interrupt [ 16.998246] JDB: dwc3_gadget_reset_interrupt [ 17.002519] JDB: dwc3_reset_gadget [ 17.005922] JDB: usb_gadget_udc_reset [ 17.062422] JDB: usb_gadget_set_state state: 5 [ 17.067069] JDB: dwc3_gadget_interrupt [ 17.070823] JDB: __dwc3_gadget_ep_enable [ 17.074745] JDB: __dwc3_gadget_ep_enable [ 17.170898] JDB: usb_gadget_set_state state: 6 [ 17.195605] JDB: usb_gadget_set_state state: 7 [ 17.200179] JDB: __dwc3_gadget_ep_enable [ 17.204118] JDB: __dwc3_gadget_ep_enable [ 17.208057] JDB: usb_gadget_vbus_draw [ 17.211721] JDB: usb_gadget_set_state state: 7 <in the good case everything is happy here> This sounds a bit like the issue in the comment here: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/usb/dwc3/gadget.c?h=v5.8-rc3#n3143 However, I've tried calling dwc3_gadget_reset_interrupt() and dwc3_reset_gadget() at the tail end of dwc3_gadget_start() but that doesn't seem to help. I was curious if you or anyone else had any thoughts on how to debug this further? thanks -john
