On Wed, 13 Jul 2011, Ming Lei wrote: > Hi, > > On Wed, Jul 13, 2011 at 11:20 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > > Why should system suspend be different from runtime suspend? �Have you > > This is also my puzzle, :-) > > > compared usbmon traces for the two types of suspend? > > Almost same. Come on. "Almost same" means they are different. That difference is clearly the important thing you need to track down. > If I add USB_QUIRK_RESET_RESUME quirk for the device, > the stream data will not be received from the device in runtime pm case, > same with that in system suspend. uvcvideo should be able to reinitialize the device so that it works correctly following a reset. If the device doesn't work then uvcvideo has a bug in its reset_resume handler. > Maybe buggy BIOS makes root hub send reset signal to the device during > system suspend time, not sure... That's entirely possible. 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
