CS4299
CS4299This is a Cirrus Logic AC'97 Audio controller This chip is sometimes incorrectly called CS4229 in IBM documentation Features
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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.
T23 Fast Sound
On at least one t23 (mine) the ALSA intel8x0 driver plays sound too fast. The following /etc/asound.conf restores normal operation:
pcm.intel8x0-hw {
type hw
card 0
}
pcm.!default {
type plug
slave.pcm "intel8x0"
}
pcm.intel8x0 {
type dmix
ipc_key 1234
slave {
pcm "hw:0,0"
period_time 0
period_size 512
buffer_size 4096
rate 44100
}
}
ctl.intel8x0-hw {
type hw
card 0
}
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.
