[alsa-devel] Analog-SPDIF dup

Takashi Iwai tiwai at suse.de
Wed Nov 21 12:20:03 CET 2007

At Tue, 20 Nov 2007 01:51:51 +0100,
Lennart Poettering wrote:
> 2) If I understood correctly, then on some devices it is possible to
>    open a analog output and a SPDIF output simultaneously and
>    independently. On others however, they are exclusive to each
>    other. The name hinting system doesn't really distuinguish
>    those cases. Any idea how I could detect this? The reason is, I'd like to
>    open both SPDIF and analog out in PulseAudio at the same time -- if
>    it is possible. If it is not I want to give the user a quick way to
>    switch the outputs.

There is no 100% certain way, so far.  A practical way would be to
open analog then SPDIF PCMs at the same time with non-blocking mode.
If both can be opened, it's likely non-duplicated one.

Or, we can change the "default" PCM to always output both.  Not sure
whether it's a good change, though.  But usually SPDIF output can be
turned off via a mixer switch, so this wouldn't be a big problem (I


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