I have been trying to get a second codec working on a computer that has

two codecs - one for the front speakers,

one for the rear panel line outs. So far I haven't been able to get this

working. I received this message from the manufacturer of the board:

"R&D has determined that the ability to have selectable or dual line-out

in the current hardware design is

limited by Linux OS kernel. The HDA sound driver did not anticipate and

did not include support for two

identical audio codecs (ALC888) in a system - therefore, the 2nd codec

cannot be successfully

initialized. To fix this issue, the Linux kernel level sound driver

(controls function) would need to be

modified to cover full functional control of the 2nd codec. This

modification is very challenging and

involves time, risk, and potential unknown side effects - because we are

talking about modifying the

kernel of the Linux OS and different version of kernel may have different

structures as well.

Do you mean multiple streaming ?

The ALC888 series are high-performance 7.1+2 Channel High Definition Audio Codecs providing ten DAC channels that simultaneously support 7.1 sound playback, plus 2 channels of independent stereo sound output (multiple streaming) through the front panel stereo outputs

Both via and adi hda codecs support multiple streaming by independent headphone, you just need to assign spec->alt_dac_nid and spec->analog_stream_alt_playback in patch_realtek.c when the hda controller support enough stream and hda codec has a dac for the headphone.