I'm running the Bunsenlabs Hydrogen distro of Linux Debian on a Acer Inspire V5 with a RealTek soundcard. I upgraded from Pd 0.46.2 to Pd 0.47.1 and discovered that Pd couldn't recognize my soundcard. This was surprising because with 0.46.2 everything worked perfectly out of the box, both MIDI and audio.
0.47.1 only offered OSS and portaudio as options even though I have both Alsa and Jack installed. Furthermore, my Alsa is completely up to date, as is my Jack (I run an apt-get update/upgrade once a month).
I have now downgraded back to 0.46.2 and the soundcard recognition and playback are both working fine again. I don't get it, but, well, there it is.
I am seriously not a boffin and couldn't possibly hope to speculate on what the deal might be, but I just wanted to report the problem.