At Tue, 26 Feb 2002 19:05:10 +0100 (CET),
Erik Inge Bolsų wrote:
> 
> On Tue, 26 Feb 2002, Takashi Iwai wrote:
> >At Tue, 26 Feb 2002 17:55:36 +0100 (CET),
> >Erik Inge Bolsų wrote:
> >> On my new PC, there's a cmipci chip built-in to the mainboard. It's noisy,
> >> but that's as expected.
> >>
> >> But there's a weird issue with it. I can play 16bit stereo 44.1khz sound
> >> just fine. 22 khz, though, is inaudible. In fact, everything but 44khz
> >> stereo 16bit gives me either white noise or inaudibility.
> >
> >comparison between registers on two states gives only the difference
> >of regisister 0x05..  that is quite normal.
> >sorry, i have no idea...
> >
> >well, could you run once arecord with 22kHz and then try aplay with
> >22kHz again?
> >
> >also, doesn't 48khz playback work, too?
> 
> Aha!
> 
> By accident, the "Exchange DAC" mixer switch was on. Turning that off, all
> works as expected...
 
ah, ok, relieved :)


> Or rather... by experimentation, I've determined this:
> 
> "Exchange DAC" switch on, "IEC958 In Monitor" switch on:
>       22050 Hz silent, 44100 Hz fine
> 
> "Exchange DAC" switch on, "IEC958 In Monitor" switch off:
>       22050 Hz silent, 44100 Hz silent
> 
> "Exchange DAC" switch off, "IEC958 In Monitor" switch on:
>       22050 Hz fine, 44100 Hz fine

ok.

> "Exchange DAC" switch off, "IEC958 In Monitor" switch off:
>       22050 Hz fine, 44100 Hz silent

i don't understand this behavior..

> Just extremely weird signal routing on this one card, or is this common?
> Please document this somewhere for others :)
 
i cannot test the card at this moment since it's out of my box.
i'll examine this later (mine is another model, so it's worthy to
check it).

there is a bit switch (front/rear exchange) in the mixer regs which
works similarly like this switch.  the switch is not implemented in
alsa, because we already have another one.  but interestingly, we can
use even both switches at the same time.


> ( Perhaps match by subsystem id and modify mixer element names
> accordingly to something sane? And/or mark all switches that have
> something to do with signal routing as such, and let a specialized mixer
> app take care of such things? )


Takashi

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