There is no fix yet. And realtek engineer told me that he met the similar problem on the Dell laptop before, but it was proven a hardware problem (headphone can't be detected).
So does the headphone work well under Windows on your machine? -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1447909 Title: external mic not detected on machines with alc256 codec Status in HWE Next: Fix Released Status in linux package in Ubuntu: Fix Released Bug description: This bug is used for tracking, please do not triage. To manage notifications about this bug go to: https://bugs.launchpad.net/hwe-next/+bug/1447909/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp