The AWG 5014 driver has two distinct "parameters" in the hardware,

• Clock source -> int or ext
• Reference oscillator -> int or ext
  

The recently updated 5014 driver introduces a 'parameter' ref_clock_source.
https://github.com/QCoDeS/Qcodes/blob/master/qcodes/instrument_drivers/tektronix/AWG5014.py#L160
This refers to using an internal or external clock and and has nothing to do with the reference oscillator, making this a confusing name.
Additionally there is no parameter that sets the reference oscillator.

The driver does contain some reference to these parameter under their proper name.
https://github.com/QCoDeS/Qcodes/blob/master/qcodes/instrument_drivers/tektronix/AWG5014.py#L847-L852

I would suggest the following fix.

• Rename the ref_clock_source parameter to clock_source.
• Add a parameter for the reference_source
  Both of these names are the names that the AWG uses internally, both in it's GUI as in it's sequencer config.

@WilliamHPNielsen as author of the recent fix, do you agree with these changes? If so I will be sending a PR shortly.