Only some of Santa's greeting returned - a problem perhaps? (2-2)

'santa's greeting returned a problem perhaps?' is the definition.
I know nothing about this answer so I cannot tell whether this works.

'only some of' is the wordplay.
I cannot quite see how this works, but
'of' could be 'o' and 'o' is present in the answer.
The remaining letters 'hoh' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?