Hello, I have a strange behabiour with sound card usb. I use kernel 3.18.11-rt7 (real-time kernel ) It takes 10 (!) seconds between detection of usb device till it is registered ("registered new interface driver snd-usb-audio") in kernel. We take the usb device out of reset using another HW. See below dmesg: [ 7.911220] ixgbe 0000:01:00.1: registered PHC device on eth1 [ 8.186213] ixgbe 0000:01:00.1 eth1: NIC Link is Up 1 Gbps, Flow Control: RX/TX [ 8.218386] NET: Registered protocol family 10 [ 8.691077] ixgbe 0000:01:00.0 eth0: NIC Link is Down [ 9.090808] ixgbe 0000:01:00.1 eth1: NIC Link is Down [ 9.893587] ixgbe 0000:01:00.0 eth0: NIC Link is Up 1 Gbps, Flow Control: RX/TX [ 10.317939] ixgbe 0000:01:00.1 eth1: NIC Link is Up 1 Gbps, Flow Control: RX/TX [ 38.171328] random: nonblocking pool is initialized [ 260.380461] usb 1-2: new full-speed USB device number 2 using xhci_hcd [ 260.545907] usb 1-2: config 1 has an invalid descriptor of length 0, skipping remainder of the config [ 260.546471] usb 1-2: New USB device found, idVendor=0451, idProduct=9010 [ 260.546478] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 260.546484] usb 1-2: Product: TI C55 Ver 6.00 [ 260.546488] usb 1-2: Manufacturer: Texas Instruments [ 260.546491] usb 1-2: SerialNumber: 320001 [ 260.594916] input: Texas Instruments TI C55 Ver 6.00 as /devices/pci0000:00/0000:00:14.0/usb1/1-2/1-2:1.3/0003:0451:9010.0001/input/input3 [ 260.595084] hid-generic 0003:0451:9010.0001: input,hidraw0: USB HID v1.11 Device [Texas Instruments TI C55 Ver 6.00] on usb-0000:00:14.0-2/input3 [ 260.595153] usbcore: registered new interface driver usbhid [ 260.595157] usbhid: USB HID core driver [ 345.706843] usbcore: registered new interface driver snd-usb-audio Is there any idea what can cause this delay ? Regards, Ran