> On Wed, 2020-07-15 at 00:51 +0000, Peter Chen wrote: > > > > > The Toradex Colibri iMX6ULL board has a special USB hardware design. > > > With runtime-pm enabled USB reset itself continuously. Furthermore > > > the OTG port is also not enumerating devices if the Chipidea IP is > > > in runtime sleep mode and a device or host gets plugged in. > > > > > > > Hi Philippe, > > > > You may describe the detail what's the special USB hardware design for > > your board, > > If I only knew the root-cause of that problem - unfortunately I don't. > That's also why I have such a hard time to describe it. > > > and why it causes the problem, and why disable runtime pm could fix > > this issue, then, > > I cannot provide the 'why' part yet. I'll try something more and hope I can provide > you guys with the exact description. > > > the other users could know if it could apply to their platforms or not > > in future. > > I only found out about it because you were pointing me in that direction. I debugged > for hours now and didn't came to the root-cause of the issue. I think to really > understand it I would need to know much more about the Chipidea IP. > > I'll get back to you guys with a proposal for a new description. > Philippe, is it possible to share your USB hardware design at 6ULL? And how ci_hdrc_gadget_connect is called when the runtime pm is disabled? Thanks, Peter