On Thu, 25 Oct 2012, Ankit wrote: > Hi Alan, > > Thanks for your response. > > Yes, there is a handling of PRC bit in xhci-hub.c > > Our query is, at the time of XHCI initialization (inserting xhci-hcd.ko and > no USB device is attached), is there PRC and CSC bits should be set? > > Our host controller sets PRC and CSC bits at the time of initialization, > even though no USB device is attached. At the time of initialization, > hub_probe() gets called and in-turn it calls hub_activate(). hub_activate() > clears the CSC bit, but PRC bit does not get cleared (in linux 3.6.1). > hub_events() has functionality to clear the PRC bit, but initially there is > no events from HUB, so hub_events() may not clear the PRC bit. Due to this > behavior, when we try to insert a USB device, interrupt does not generate > (because, earlier, PRC bit was set and not cleared) and USB device does not > get enumerated. > > So, would you please tell us, what should be the behavior? I believe the hub driver needs to clear the USB_PORT_FEAT_C_RESET and USB_PORT_FEAT_C_OVERCURRENT features along with the other ones in hub_activate(). Would you like to submit a patch to do this? 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
