I have same problem with HP Pavilion dv9297ea but I have a workaround (see laptop testing page, community supplied laptops for full report).
Basically, press mute, plug in phones, then unmute. sound comes through phones and not main speaker. To reverse, press mute, unplug phones, then unmute...sound now comes through main speakers again. -- headphones jack doesn't mute speakers on lenovo 3000 n100 https://launchpad.net/bugs/88546 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
