snd_via8233(4) VIA Technologies VT8233 bridge device driver


To compile this driver into the kernel, place the following lines in your kernel configuration file:
device sound device snd_via8233

Alternatively, to load the driver as a module at boot time, place the following line in loader.conf5:



The bridge driver allows the generic audio driver, sound(4), to attach to the VIA VT8233 audio devices. These audio chipsets are integrated in the southbridge on many VIA based motherboards.

Runtime Configuration

The following sysctl(8) variables are available in addition to those available to all sound(4) devices:

Experimental polling mode, where the driver operates by querying the device state on each tick using callout(9). Polling is disabled by default. Do not enable it unless you are facing weird interrupt problems or if the device cannot generate interrupts at all.


The driver supports the following audio chipsets:

  • VIA VT8233
  • VIA VT8233A
  • VIA VT8233C
  • VIA VT8235
  • VIA VT8237
  • VIA VT8251


The device driver first appeared in Fx 4.7 .


This manual page was written by An Joel Dahl Aq [email protected] .


The driver does not support S/PDIF. There is partial support in the code, so implementing it should be fairly easy if the right hardware is available.