On Wed, Oct 14, 2015 at 02:22:59PM +0200, Simon Wolk wrote:
I am using an old Benq notebook (Joybook S73) mit Xubuntu 15.04. When I installed a new kernel (then 3.19.0-16, but now I am using 3.19.0.28) the sound on the speakers stoped working and there were no more audible sounds. With headphones plugged in and a the highest possible volume I could hear very silent the music played on the PC.
Up to Kernel 3.2.0-70 the sound worked fine.
Does 3.2.0-70 still work fine?
A friend's laptop had an electrostatic discharge or electrical event that damaged the audio codec chip, taking out the headphone detect and headphone amp, and it showed almost same symptoms as you describe. On that laptop, patching the kernel to force the headphone not present fixed playback from speakers. I'm not suggesting that, but if you can say the old kernel still works fine you can exclude damage as cause.
That leaves you with looking at the difference between 3.2.0 and 3.19.0, for the driver in use.
Try other kernels between the two, to figure out which kernel introduced the change.