If I understand you correctly, I should plug in headphone to the front panel and then follow this guide: https://wiki.ubuntu.com/PulseAudio/Log and collect a log for a few minutes? I have attatched the result of alsa-info.
** Attachment added: "alsa-info.txt.CnsFIG0dVc" https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/1213769/+attachment/3839370/+files/alsa-info.txt.CnsFIG0dVc -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1213769 Title: [ASUS P8Z68-V PRO, Realtek ALC892, Green Line Out, Rear] Popping sound or crackle every few seconds while playing audio To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/1213769/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
