Spyder5 Monitor Calibration Ubuntu 14.04

I've just experienced this same issue with my new Spyder5 on Ubuntu 14.04. For the sake of completeness, (and for my own future self googling this :-), I'll add all issues I've ran into and their solution:

Problem: dispcalGUI does not detect the instrument at all

Solution: Argyll CMS needs to be downloaded and installed manually, as stated in the first step of the dispcalGUI Quickstart Guide. After installing, run dispcalGUI, select File -> Locate Argyll CMS executables and locate the bin folder of your Argyll CMS installation.

Problem: Calibrate & profile fails with Error - new_disprd() failed with 'Instrument Access Failed'

Solution: Check if /etc/udev/rules.d/55-Argyll.rules exists. If not, copy it from the Argyll install directory (or downloaded package). It is in the folder usb/. Then reboot the system or at the very least, unplug the device and plug it back in again. More info can be found in the Argyll installation manual.

USB 2 / 3

Apparently there might be issues when using some devices on an USB 3 port. If possible, try switching it to an USB 2 port and see if this helps. In my case it was not necessary, the Spyder5 runs fine on my USB 3 port.

Last resort

If all else fails, you could run either Windows or OS X on a separate partition and do the calibration there using the vendor software. The resulting ICC profile is compatible across operating systems, so it is possible to import it to Linux. I haven't looked into this in detail as dispcalGUI seems to be working now for me.