Yesterday when I opened my laptop I noticed that I no longer had sound from the built-in speakers. I carefully checked settings in Sound Preferences, and then dropped to shell and looked in alsamixer. Nothing is showing muted or 0/no volume. Everything is on and set to max volume. The profile is Analog Stereo Duplex, the default.
Sound works fine when using headphones.
I compared my alsa conf files with samples from known good systems and am not finding any difference.
I'm runnning out of ideas and even updated my kernel to 3.8.8 in hopes that would shake this loose. No dice there, so I purged that and am back to the factory kernel 3.5.0.
Here are my current specs:
RELEASE=14 CODENAME=nadia EDITION="MATE 64-bit" DESCRIPTION="Linux Mint 14 Nadia" DESKTOP=MATE TOOLKIT=GTK
00:1b.0 Audio device: Intel Corporation 7 Series/C210 Series Chipset Family High Definition Audio Controller (rev 04)
cat /proc/asound/card0/codec#* | grep Codec
Codec: IDT 92HD91BXX Codec: Intel PantherPoint HDMI astembridge-Inspiron-5720
**** List of PLAYBACK Hardware Devices **** card 0: PCH [HDA Intel PCH], device 0: STAC92xx Analog [STAC92xx Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: PCH [HDA Intel PCH], device 3: HDMI 0 [HDMI 0] Subdevices: 0/1 Subdevice #0: subdevice #0
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EDIT 1: The laptop itself is less than a month old and never dropped or otherwise mistreated. It is a Dell Inspiron 17R - 5720.
EDIT 2: (March 2016 update). Got this old laptop out again. I installed a fresh copy of Win7 yesterday in hopes it might have been a weird nix issue. Nope. Windows showed the audio driver installed and working properly, and when I played a track I can see the sound meter bouncing up & down. Just no audio from either speakers or headphone jack.