On Thu, Jul 16, 2020 at 8:31 PM Peter Chen <peter.chen@xxxxxxx> wrote: > > On 20-07-16 13:24:52, Rob Herring wrote: > > On Tue, Jul 14, 2020 at 05:18:20PM +0200, Philippe Schenker wrote: > > > Chipidea depends on some hardware signals to be there in order > > > for runtime-pm to work well. Add the possibility to disable runtime > > > power management that is necessary for certain boards. > > > > This is why we have SoC specific compatible strings. Use that. > > It is a board design limitation, not SoC's. To support USB low power > mode for device mode, either VBUS connects to SoC, or VBUS connect to > GPIO, or VBUS connect to Type-C IC, but none of the design is used > at that board. So the USB can't enter low power mode for that board, > otherwise, the USB controller can't be woken up since no any interrupts > will occur if USB cable (host at other side) connects to the connector. That's certainly a better explanation than the original. Don't you need to describe the Vbus connection in the above cases? Then you could handle this case based on the lack of a Vbus description? Rob