On Fri, 19 Aug 2016, ludeng wrote: > Hi, > How the EHCI HC driver make the decision to suspend some USB devices, > but not to suspend some others? We notice that for some USB Video > Cameras, when they are enumerated and there is no data to transfer, > the EHCI HC driver will suspend them by setting the Suspend bit of > the PORTSC register. But for some other Cameras, the EHCI HC driver > will not suspend them. The drvier make the decision based on what > kind of information of the device ? The EHCI driver does not make this decision. The decision is made by the video camera driver and by the user. Alan Stern -- 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