Marking as invalid since - as you wrote - it was an volume related issue and
not a kernel/driver bug.
I didn't checked alsa because I didn't touched low-level tools willigly to
avoid messing with pulseaudio.
Perhaps pulseaudio brought both volumes to zero crashing sometime ago and I
didn't notic
Your headphones might be muted. Please run the alsamixer program (type
alsamixer in terminal) and see if you can control the headphone volume
there.
Simple mixer control 'Headphone',0
Capabilities: pvolume pswitch
Playback channels: Front Left - Front Right
Limits: Playback 0 - 64
Mono:
** Attachment added: "AlsaDevices.txt"
http://launchpadlibrarian.net/30429756/AlsaDevices.txt
** Attachment added: "BootDmesg.txt"
http://launchpadlibrarian.net/30429757/BootDmesg.txt
** Attachment added: "CRDA.txt"
http://launchpadlibrarian.net/30429758/CRDA.txt
** Attachment added: "
