>> From: Hao Wu <hao.wu@xxxxxxxxx> >> >> Update PCI suspend/resume function to fix suspend/resume issue. This >> modification will make sure in D3, Vbus is powered off, both client/host >> function will be stopped and controller moves to OTG IDLE state. Once it >> resumes back to work, state machine will restart from the IDLE state, and move >> to host/client based on inputs event. > >Even though this patch isn't present in the revised patch series, I >still wanted to ask a question about it. Why should Vbus be powered >off in D3? Isn't the bus supposed to remain powered while everything >is suspended? Otherwise how can you detect plug/unplug events? > Really thanks for patch review. : ) The actual purpose is to save power as much as possible for Intel MID platform. And OTG devices should turn off the Vbus when user doesn't want to use the USB bus to save power per OTG State machine in Spec, D3 is the same case. So VBus is powered off in D3. In D3, although Vbus is off and its OTG state is in IDLE, other OTG events are all available. It can detect cable remove/connect via id changes and detect VBus changes as well. Thanks Hao -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
