Displayport/HDMI sound output channels reversed

[Matthew Saltzman]

I have a Dell Latitude E6410 (running up-to-date F20 and the nvidia
display driver) with a displayport alternate video output.  I use a
displayport-HDMI converter to run videos to a TV screen.

When I configure sound to play through the displayport/HDMI output, the
left and right channels are reversed.  Running the sound setup tool, I
test the speakers and the left speaker test plays through the right
speaker and vice versa.

Anybody else seen this?  Is there a setting that can be changed
someplace?  Or is this a bug?  Or both?

TIA.