AD1981B

AD1981B This is a Analog Devices AC'97 Audio controller Note: The documentation of the R40 incorrectly(?) states it has a AD1891A Features Chipset: AD1981B Interface: AC'97 PCI-ID: 8086:24c5

Linux OSS driver

On systems where lspci shows an Intel AC'97 Audio Controller, this chip is supported by the i810_audio kernel module.

Linux ALSA driver

On systems where lspci shows an Intel AC'97 Audio Controller, this chip is supported by the snd-intel8x0 kernel module. This driver provides enhanced power saving capabilities.

On systems where lspci shows an ATI AC'97 Audio Controller (R40e and R51e), this chip is supported by the snd-atiixp kernel module.

Note

On some models (T40, T43p, ... R51e ...) audio is muted if either Headphone or Line Jack are unmuted. See also ALSA Wiki FAQ [1]. Also, if Headphone Sense or Line Jack Sense are unmuted audio is dead (R52, X40). By default the Sense settings are not shown in GNOME.

Note

A bug was introduced in the 2.6.20 kernel (between the rc1 and rc2 releases) which causes the sound to stop working after hibernation. Rebooting does not seem to fix the problem. A quick work-around is to do a suspend-to-ram, and then wake the machine up. This issue is chronicled in this bug report on Launchpad.net: The fix changing HIBERNATE_MODE=shutdown to HIBERNATE_MODE=platform in /etc/default/acpi-support worked very well. I don't know if it possibly could introduce other bugs or if it's a true fix.

https://bugs.launchpad.net/ubuntu/+source/linux-source-2.6.20/+bug/80893

Changing HIBERNATE_MODE=shutdown to HIBERNATE_MODE=platform in /etc/default/acpi-support seems to be solving this issue for many users. Confirmed to work with: X31, T43p

FreeBSD OSS driver

snd_ich will work happily for this audio chip.

ThinkPads this chip may be found in

• G40
• R40, R40e
• R50, R50e, R50p, R51, R51e, R52
• T40, T40p, T41, T41p, T42, T42p, T43, T43p
• X30, X31, X32
• X40, X41, X41 Tablet

See also

• Problem with audio clipping