On Tue, 21 Apr 2015, Tom Yan wrote: > On 21 April 2015 at 03:44, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > > The generic driver includes code for enabling wakeup by default, > > Is there a part of code which can shows this? It seems to me that the > usbhid module is loaded for all USB HID devices, so I doubt a bit: > > [tom@localhost ~]$ journalctl -b -1 | grep hid > Apr 21 05:00:36 localhost kernel: hidraw: raw HID events driver (C) Jiri Kosina > Apr 21 05:00:36 localhost kernel: usbcore: registered new interface > driver usbhid > Apr 21 05:00:36 localhost kernel: usbhid: USB HID core driver > Apr 21 05:00:36 localhost kernel: hid-generic 0003:046D:C52E.0001: > input,hidraw0: USB HID v1.11 Keyboard [Logitech USB Receiver] on > usb-0000:00:14.0-14/input0 > Apr 21 05:00:36 localhost kernel: hid-generic 0003:046D:C52E.0002: > input,hiddev0,hidraw1: USB HID v1.11 Mouse [Logitech USB Receiver] on > usb-0000:00:14.0-14/input1 > > [tom@localhost ~]$ journalctl -b -2 | grep hid > Apr 21 04:59:58 localhost kernel: hidraw: raw HID events driver (C) Jiri Kosina > Apr 21 04:59:58 localhost kernel: usbcore: registered new interface > driver usbhid > Apr 21 04:59:58 localhost kernel: usbhid: USB HID core driver > Apr 21 04:59:58 localhost kernel: logitech-djreceiver > 0003:046D:C52B.0003: hiddev0,hidraw0: USB HID v1.11 Device [Logitech > USB Receiver] on usb-0000:00:14.0-13/input2 > Apr 21 04:59:58 localhost kernel: logitech-hidpp-device > 0003:046D:4024.0004: input,hidraw1: USB HID v1.11 Keyboard [Logitech > K400] on usb-0000:00:14.0-13:1 > > [tom@localhost ~]$ lsusb -t > /: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/6p, 5000M > |__ Port 1: Dev 2, If 0, Class=Mass Storage, Driver=usb-storage, 5000M > /: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/14p, 480M > |__ Port 13: Dev 2, If 0, Class=Human Interface Device, Driver=usbhid, 12M > |__ Port 13: Dev 2, If 1, Class=Human Interface Device, Driver=usbhid, 12M > |__ Port 13: Dev 2, If 2, Class=Human Interface Device, Driver=usbhid, 12M > |__ Port 14: Dev 3, If 0, Class=Human Interface Device, Driver=usbhid, 12M > |__ Port 14: Dev 3, If 1, Class=Human Interface Device, Driver=usbhid, 12M > /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/2p, 480M > |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/8p, 480M > /: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/2p, 480M > |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/6p, 480M You see this because logitech_djreceiver overrides the setting of the ll_driver field in struct hid_device. Briefly, usbhid/hid-core.c initializes the wakeup setting in usbhid_start(), which is the .start member of usb_hid_driver, which is assigned (in usbhid_probe()) to hid->ll_driver. But the logi_dj_recv_add_djhid_device() routine in hid-logitech-dj.c changes dj_hiddev->ll_driver to &logi_dj_ll_driver, and its .start member is logi_dj_ll_start(), which does not initialize the wakeup setting. Since usbhid_start() never gets called, the device doesn't get enabled for wakeup. See the logi_dj_probe() routine for more details about how this works. 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
