On Sun, 11 Nov 2012, Lan Tianyu wrote: > Hi Alan: > Great thanks for your review and good suggestions. > I think the main problem is that when the port device resumed(you said > turn on/off power in the port's runtime callback ) and device powered on > again, If we did't resume the device and suspend again, the device would > be at uninitalized state(I guess it should be unattached state actually) > until resume it, right? No. The device will be in the POWERED state at first, but it will quickly change into the SUSPENDED state. > This will consume more power than suspend it > agian. No it won't, because the device will suspend itself after 3 ms. > So from my opinion, the device should be resumed when port > resumes. After autosuspend delay timeout, the device will suspend again. > If I remember correctly, pcie port and sata port do the same thing that > port will resume its children when it resumes. That doesn't mean USB has to do the same thing. 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
