John Stultz <john.stultz@xxxxxxxxxx> 于2020年7月3日周五 上午11:08写道： > > On Thu, Jul 2, 2020 at 7:55 PM Jun Li <lijun.kernel@xxxxxxxxx> wrote: > > John Stultz <john.stultz@xxxxxxxxxx> 于2020年7月3日周五 上午5:46写道： > > > I was curious if you or anyone else had any thoughts on how to debug > > > this further? > > > > If you force your gadget to be USB2(e.g. in dts) > > > > + maximum-speed = "high-speed"; > > > > will you still reproduce this issue? > > Thanks for the suggestion! Unfortunately, I gave that a try, but still > reproduced the same issue with this setting. > > Curious, what the issue is your were thinking this would help with? I had experience device mode had problem on super speed channel with some switch device between the host and type-C port, then it will not downgrade to enable USB2 term so host can't detect the my board's typec-C port. > > > Does your gadget connect to host super speed port directly via a C-to-A cable > > in your test labs? or there is something between? > > I'm not sure of the details in the lab, however I can reproduce this > on my desk with a Host machine <-> USB hub <-> USB-C port. > > Additionally, the board itself is a little complicated, in that the > USB-C port is USB2 only (however, it does have two USB-A USB3 ports > behind an on-board hub and a switch to decide if the USB-C or hub > ports are enabled since there is only one usb controller). So actully you should limit the gadget speed to be high speed for your USB2 only type-C port. Does the host machine can detect the connection when you plug in? Li Jun > > thanks > -john
