Generic HDA drivers in Linux (ALSA) could play sound, but microphones often didn't work, headphone jacks wouldn't switch automatically, or the audio would be extremely quiet.
Before attempting any fixes, you must understand what the datasheet promises and the chip's hardware limitations. This knowledge is the key to identifying whether a problem is a software bug, a system conflict, or a physical defect in the hardware.
Optimizing the CX31993 DAC: Datasheet Insights, Common Fixes, and How to Make It Better The Conexant (CX-Pro) CX31993 Go to product viewer dialog for this item. cx31993 datasheet fix better
If you have a PinePhone, PineBook Pro, or a similar ARM device and your audio is "broken" (static, quiet, mic muted), here is how to apply the "better" fixes.
It is a "plug-and-play" solution compatible with a wide range of devices, including: : iPhone 15 series, iPad Pro/Air (USB-C models). : Samsung Galaxy S-series, Google Pixel. : Windows 10/11 and macOS. Amazon.com for a DIY repair, or are you trying to compare different dongles that use this chip? AUDIOCULAR Conexant CX Pro CX31993 USB-C DAC & Amp Generic HDA drivers in Linux (ALSA) could play
The OEM version (consumer dongles) is generally not user-updateable. Only OEM manufacturers or Chromebooks using the "Synaptics CAPE" plugin can flash the chip to fix host-specific bugs.
To force the CX31993 to accurately read your headphones' impedance and deliver the correct voltage: Disconnect the CX31993 dongle from your phone or PC. : Samsung Galaxy S-series, Google Pixel
The chip reads the impedance only at the moment of insertion .
allows for direct hardware volume control, unlocking the full 2 Vrms output. FreeBSD Auto-Config: For those using it on FreeBSD, adding hw.snd.default_auto=2 /etc/sysctl.conf
| Issue | Description | |-------|-------------| | | No public datasheet details the I²C/HID registers for advanced features (e.g., gain control, filter settings, LED control). | | Incorrect Pinout Diagrams | Several community copies show contradictory pin functions for pins 9, 10, and 11 (e.g., VDDIO vs. GPIO). | | Undocumented Modes | Behavior in "firmware-less" vs. "EEPROM configuration" mode is not clearly defined. | | Electrical Typos | Some sources list VDD as 3.3V max, others 5V – critical for design safety. | | Missing Timing Diagrams | No reset timing or I²S slave mode timing constraints are available. |