Created attachment 660605 [details]
alsa-info.txt from host big41's TW5 installation

Y2logs for big41's plasma5 installation are attached to bug 929016

I have two 64 bit TW installations on the same Intel machine. One installation
has breeze* and kde-oxygen-fonts locked out, preventing plasma5 from displacing
any more than necessary of plasma4. Other than the default TWM and IceWM, and
KDE, no other DEs are installed on either. Sounds work normally on the "kde4"
installation. On the plasma5 installation, systemsettings -> multimedia listed
no playback devices or backends to choose from, and made no sounds. This was
the selection of installed packages on the plasma5 installation before its
system sounds started to work:
alsa-1.1.0-1.1.x86_64
alsa-firmware-1.0.29-1.1.noarch
alsa-oss-1.0.28-3.3.x86_64
alsa-plugins-1.1.0-2.1.x86_64
alsa-plugins-pulse-1.1.0-2.1.x86_64
alsa-utils-1.1.0-1.2.x86_64
kmix-15.08.3-1.1.x86_64
libQt5Multimedia5-5.5.1-1.1.x86_64
libphonon4-4.8.1-1.3.x86_64
libphonon4qt5-4.8.3-3.1.x86_64
libpulse-mainloop-glib0-7.1-1.1.x86_64
libpulse0-7.1-1.1.x86_64
phonon-backend-gstreamer-4.8.2-2.1.x86_64
plasma5-workspace-5.4.3-1.1.x86_64
pulseaudio-7.1-1.1.x86_64

As in the KDE4 installation, aplay --v /usr/share/sounds/alsa/test.wav produced
expected output after having run set_default_volume -f 0 and adjusting levels
with alsamixer. Youtube HTML5 worked as expected in both as well.

Manually installing phonon4qt5-backend-gstreamer-4.8.2-2.1.x86_64 got the
plasma5 sounds working. If plasma5 can't make sounds without it, something
ought to require it.