Missing audio output device

I cannot get sound over the Display Port from a Dell E6400 laptop equipped with an NVidia Quadro NVS 160M. I’m using a fresh (and up to date) installation of the CentOS 7, with NVIDIA 340.102 drivers.
Driver is installed, video works fine and I can switch between the built-in screen and a SONY TV connected to the Display Port (or use both at the same time). But sound is only available from the laptop speakers. ‘aplay -l’ shows analog speakers as the only playback device available.

My goal is to have audio transmitted via the HDMI / Display Port directly to the TV.

The bug report tool output is here.

Any help to troubleshoot this is highly appreciated!