I have a roughly month-old installation of Ubuntu 16.04 on a Dell XPS 13. Until today, my speakers and headphones worked more or less flawlessly. A single device appeared in the "Play sound through" list in the "Sound Settings" dialog (regrettably, I don't remember what it was called).
Today, I opened up an old Audacity project and noticed that the sound was coming through the built-in speakers, even though I had headphones plugged in. I played around in "Sound Settings" a little, and in particular I tried selecting the various HDMI output settings in the "Mode" dropdown, instead of the blank line that was selected by default.
Now, no devices appear in the "Play sound through" list, even though
aplay -l lists the same devices it always has:
**** List of PLAYBACK Hardware Devices **** card 0: PCH [HDA Intel PCH], device 0: ALC3246 Analog [ALC3246 Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: PCH [HDA Intel PCH], device 3: HDMI 0 [HDMI 0] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: PCH [HDA Intel PCH], device 7: HDMI 1 [HDMI 1] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: PCH [HDA Intel PCH], device 8: HDMI 2 [HDMI 2] Subdevices: 1/1 Subdevice #0: subdevice #0
gives no audio output. However, running
aplay -D plughw:0,0 /usr/share/sounds/alsa/Front_Center.wav
gives the expected output—through my headphones if they're plugged in, and through the built-in speakers otherwise.
The settings in
alsamixer look fine, although I noticed one strange thing: at some point, the master volume changed itself from 66 (where I set it last) to 41, for no apparent reason.
pulseaudio, rebooted several times, and done a cold reboot, to no avail. I just want everything back the way it was last week...