On Wed, 11 Feb 2015, Dave Mielke wrote: > [quoted lines by Alan Stern on 2015/02/11 at 10:13 -0500] > > >What do you mean by "turned off"? When the device is turned off, does > >it appear to the host controller that the device has disconnected from > >the USB bus? > > No. This also occurs after connecting the device while it's turned off. In this > state, the device is connected. When, with its switch in the off position, I > connect it, my log shows: > > kernel: [6125541.188647] usb 5-3: New USB device found, idVendor=10c4, idProduct=ea80 > kernel: [6125541.188659] usb 5-3: New USB device strings: Mfr=1, Product=2, SerialNumber=3 > kernel: [6125541.188667] usb 5-3: Product: CP2110 HID USB-to-UART Bridge > kernel: [6125541.188673] usb 5-3: Manufacturer: Silicon Laboratories > kernel: [6125541.188679] usb 5-3: SerialNumber: 0012EC89 > kernel: [6125541.287283] hid-generic 0003:10C4:EA80.0011: hiddev0,hidraw2: USB HID v1.11 Device [Silicon Laboratories CP2110 HID USB-to-UART Bridge] on usb-0000:00:13.0-3/input0 > mtp-probe: checking bus 5, device 12: "/sys/devices/pci0000:00/0000:00:13.0/usb5/5-3" > mtp-probe: bus: 5, device: 12 was not an MTP device > > >Which signal? Is this the signal for URB completion or the signal for > >device disconnection? > > Completion. urb->signr is set to 34 (SIGRTMIN), and that's the signal I'm > getting. So you're getting a signal indicating URB completion, but the REAP ioctl doesn't return. That is indeed very strange. You should try using usbmon to see what's going on at a lower level. 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
