在阅读了很多推荐后，我终于购买了 Focusrite Scarlett 2i4 并安装了 ubuntu studio。我在 amd64 桌面上运行 Ubuntu 14.04。
$ uname -rvi
3.13.0-46-generic #76-Ubuntu SMP Thu Feb 26 18:52:13 UTC 2015 x86_64
当插入时，内核会识别该设备。
$ dmesg
...
[14973.155287] usb 3-2: new full-speed USB device number 7 using ohci-pci
[14973.355783] usb 3-2: not running at top speed; connect to a high speed hub
[14973.370772] usb 3-2: New USB device found, idVendor=1235, idProduct=800a
[14973.370784] usb 3-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[14973.370791] usb 3-2: Product: Scarlett 2i4 USB
[14973.370797] …