ac97(4)

ac974

Generic ac'97 codec driver

Overview

AC'97 codecs contain the analog to digital (A/D), digital to analog (D/A), and mixing circuitry of many modern sound cards. AC'97 codecs, for the most part, do not talk to host buses like the PCI bus directly. Instead, they communicate through an interface chip, called the host controller. The Ensoniq AudioPCI 97 (see eap(4)) is an example of such a host controller.

Unlike many drivers, the ac97 driver does not appear in the configuration file. Instead, the driver is automatically attached by the drivers that require it.

Releases

56 releases since OpenBSD 2.6; the text changed 12 times.

  1. 2.6
  2. 2.7
  3. 2.8
  4. 2.9
  5. 3.0
  6. 3.1
  7. 3.2
  8. 3.3–3.7
  9. 3.8–4.0
  10. 4.1
  11. 4.2–4.4
  12. 4.5–4.6
  13. 4.7–8.0

Bugs

The ac97 driver does not keep track of the current user settings and instead relies on the hardware to do this.

The ac97 driver could do more to detect mixer channels that don't work and cull them from the list.

From man 8.0-current-20261101 in OpenBSD 8.0-current (2026-11-01). Parsed by carta from the page's mdoc source.