S/PDIF on X220/X230 and other Sandy/Ivy Bridge Thinkpads

Introduction

It turns that out many of the HD Audio chips on the xx20 & xx30 series Thinkpads have a pin for S/PDIF out. These are not connected on the board and not enabled in software. With some hacking you can enable it in software. When I get some SPIDF hardware I'll do some testing to see if it actually works....

The CX20672 Audio IC

Pin 39 on the chip is S/PDIF out. (In the T420 the same chip is used and this pin is labeled SPIDF). The chip is a QFN-40 (Quad flat no lead). Its not impossible to solder a wire to it but it will be pretty difficult.

Location of the pin on the schematic/board

Actual board picture

Enabling SPDIF in Software

For Linux only.

• Disable pulseaudio
• Try pulseaudio --kill
• If pulseaudio automatically starts back up again try
• systemctl --user stop pulseaudio.socket pulseaudio
  
• Use hdajackretask and override pin 0x20 or 0x22 and apply
  
  
• Restart pulseaudio with either
• pulseaudio --start
• OR systemctl --user start pulseaudio.socket pulseaudio
• Check system sound settings