Description of problem: As of Linux 4.2+ the supported ACPI revision reported back to BIOS is set statically to '2' to match Windows behaviour. This breaks audio on Dell XPS 13 , since BIOS forces ASoC to operate in I2S mode that even Linux 4.3 does not support properly yet. There is a work around that allows the reported ACPI revision to be forced via kernel parameter http://mailman.alsa-project.org/pipermail/alsa-devel/2015-May/092051.html. So it would be nice to have CONFIG_ACPI_REV_OVERRIDE_POSSIBLE=y added to the Linux 4.2+ builds Version-Release number of selected component (if applicable): Linux 4.2+ How reproducible: Persistent Steps to Reproduce: 1. Operate FC23 using 4.1.x kernel and make sure that ASoC is in HDA mode. 2. Update kernel to 4.2+. Actual results: Audio is broken, i.e. only built-in speakers work. No MIC, crappy sound out of the headphone output. Toggling things in alasmixer doesn't help much. Expected results: Fully working audio system. Additional info:
The proper solution here is to update your firmware to revision A05 or newer, this makes the ACPI override unneccesary.
*** This bug has been marked as a duplicate of bug 1255070 ***