A further observation today: Turning the laptop on from cold, the speakers appeared in the Sound pane as expected. When testing the Videos app, the sound played normally at first but a few crackles were heard. This seemed to have coincided with setting the display to Full Screen. The sound from the speakers then disappeared completely.
On executing a restart, there was nothing listed in the "Play sound through pane". After two further restarts, the Built-in Speakers were listed but accompanied by settings for HDMI/Video port showing options of HDMI sound. This persisted after another restart. I turned on a pair of Bluetooth headphones and these subsequently appeared in the "Play sound through" panel with options for Telephony Duplex (HSP/HFP) or High Fidelity Playback (A2DP) being offered. The Test Sound button payed the test signal correctly through the headphones. When re-selecting Speakers, Built-in Audio, the correct Settings for Speakers (Balance and Greyed-out Fade and Subwoofer) appeared. The Test Sound button allowed the left and right speakers to be tested as normal. This suggests that the kernel loses its connection to the speakers which is not necessarily reset on restart. However, the operation of switching between Bluetooth headphones and the speakers does seem to restore the connection and the correct functionality. I should be happy to test out the latest kernel software but I need advice as to how to do this (files to download and commands to execute via terminal) if anyone is able to help on this. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1402194 Title: PCI/internal sound card not detected To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/1402194/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs