CS4299

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Revision as of 13:44, 18 May 2006 by SystemParadox (Talk | contribs) (Dmixing)
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CS4299

This is a Cirrus Logic AC'97 Audio controller

This chip is sometimes incorrectly called CS4229 in IBM documentation

Features

  • Chipset: CS4299
  • Interface: AC'97 2.1

Linux OSS driver

This sound chip is supported by the i810_audio kernel module.

Linux ALSA driver

This sound chip is supported by the snd-intel8x0 kernel module.

Dmixing

The CS4299 is not capable of hardware mixing. This means that only one sound stream can be played at any time. You must get the software to do the mixing for it (this will load your CPU). The ALSA implementation of this is called DMIX. You can also run sound servers like ESD or ArtsD, but not all applications will use them. Recent ALSA distributions have dmixing setup and enabled by default.

Otherwise just add the following to /etc/asound.conf :

  pcm.dsp0 {
      type plug
      slave.pcm dmix
  }
  # mixer0 can stay unchanged, because
  # it isn't used anyway, I guess ;)
  ctl.mixer0 {
      type hw
      card 0
  }

Now the only problem is how to tell applications to use the DMIX channel instead of dsp0. Most applications work by specifying "dmix" as the device. For command line apps use "aoss".

Hint: XMMS does not work well with dmix and the intel8x0. You will probably need to patch and recompile.

See: XMMS bug 1716, XMMS bug 2009 and XMMS bug 1991

You also need to disable mmap and increase the buffer and period time in the advanced options.

ThinkPads this chip may be found in