I have reservations about the usefulness of including __func__ and __LINE__
in debug messages. In a nutshell, it requires the logs to be correlated
(exactly?) with the source used to build the driver. And at that point
I think other mechanism - e.g. dynamic trace points - are going to be
useful if the debug message (without function and line information)
is insufficient to pinpoint the problem.

This is a general statement, rather than something specifically
about this code. But nonetheless I'd advise against adding this
information here.

Thankyou Jakub and Simon for the suggestions.
I'll remove both in the next version.