On Thu, 3 Mar 2016, yoma sophian wrote: > hi all: > When I porting my platform ehci driver on kernel v4.1, > I get back trace like below without plug in any device and just insert > usb-common.ko, usbcore.ko and ehci-hcd.ko. > (and detail is show in the attachment) > > It seems caused by the PM related thread that is wakened up, even > there is no device plug in and step in null pointer. > Is there any callback function or flag in ehci-platform.c that we > should check that will trigger the related PM work thread? The work thread is triggered in order to suspend the EHCI controller's bus. > Appreciate your kind help in advance, > > > Backtrace: > [<bf04ebec>] (ehci_handle_start_intr_unlinks [ehci_hcd]) from > [<bf04ffb0>] (ehci_bus_suspend+0x388/0x464 [ehci_hcd]) Since there aren't any devices registered on the USB bus yet, ehci_handle_start_intr_unlink() should do nothing. It iterates over ehci->intr_unlink, but that list should be empty. 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