On Thu, Sep 13, 2018 at 03:40:12PM -0700, Rob Weber wrote: > Hi linux-usb, > > I'm currently bringing up a custom board that uses a CherryTrail > processor and I'm having quite a bit of trouble accessing the dual-role > port from Linux. > > Our system includes two USB 3.0-capable ports with Type-C connectors. > One port is designed to be a host-only port (downstream-facing), > while the other port is designed to be a dual-role port. The USB 2.0 > data lines and the SuperSpeed lines are connected to the SoC. Our > system uses two USB Power Delivery controllers to help with PD > negotiations. We have an OTG_ID signal connected to the SoC. > Depending on the data role negotiation (which we detect from the PD > controller), we either tie that signal to GND or let it float. > I'm running a 4.9.115 kernel built using Yocto with a few patches applied > to enable HDMI audio.
4.9 is really old by now, and lots and lots of USB-C and dwc3 and xhci changes have happened in the almost 2 years since that kernel was released. You might want to try 4.18 to see if your issues are already solved, have you tried that? thanks, greg k-h
