[pulseaudio-tickets] [PulseAudio] #624: need proper support for Terratec EWS88-MT (ice1712)

[PulseAudio]

#624: need proper support for Terratec EWS88-MT (ice1712)
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  Reporter:  aelschuring  |       Owner:  lennart          
      Type:  defect       |      Status:  new              
 Milestone:               |   Component:  module-alsa-*    
Resolution:               |    Keywords:  ews88 profile-set
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Comment(by lennart):

 Replying to [comment:28 aelschuring]:
 > I've posted a patch on alsa-devel today to at least get the patch for
 front:0 merged. I'm also experimenting with a solution that will allow PA
 and other applications to access front: and spdif: at the same time, which
 is currently not possible because any access to one of the channels will
 cause the entire device to be locked. That's a fundamental property of
 ALSA, and I think any solution I can come up with will be hackish.

 Depending on something like dmix for this woulde certainly be suboptimal.
 I must really say the ICE1712 design is really awful. ;-)

 > Is there a difference between the iec958: and spdif: devices? Because
 currently the card defines only the first of the two.
 >
 > We could probably ask for fourch: and sixch: definitions, but I don't
 think the ALSA guys will really like them. At least they do make more
 sense than surround* definitions, but there is just one minor issue: ALSA
 uses one configuration file for all ice1712 cards (no subsystem-id
 separation possible in ALSA), so I'm really hoping to keep that file as
 generic as possible: I'm currently leaning towards only three devices,
 which are front:, spdif: and an all-channel (8) definition.

 But it sucks a bit that you have to open an 8ch stream on a device that
 only has 4ch plugs actually soldered on.

 But then again, at some level we need to add the additional null channels.
 And I guess that work should be done at one place and one place only.
 Since PA already does some channel rearrangements it probably does make
 sense to export the audio device as 8ch device to PA and then have PA
 synthesize the extra null channels, however not expose them for volume
 control and suchlike.

 Currently PA assumes that the channels of the PCM stream it sends to the
 device and the channels of the volume control it exposes for that are
 identical. I guess it is time to end that and disuitnighs both channel
 maps. In this case we might have more streams in the PCM stream than we
 want to show in the mixer UI. And for some devices the other way round is
 true as well (i.e. stereo stream with 2.1 volume control for LFE).

 So I have now added another item to my todo list: to make that destinction
 between volume and PCM channel maps.

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Ticket URL: <http://pulseaudio.org/ticket/624#comment:29>
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