building a mixer

building a mixer

[Pieter Palmers]

Hi all,

is it possible to support multiple mixers in one card?
I have the following situation:
The card consists of a Maestro2E PCI controller with AC97 codec. On the 
expansion port of the maestro is a SAM9707 device. I'd like separate 
mixers for the AC97 and the SAM, because the control names can be very 
confusing otherwise (i.e. Master volume of Codec does not change Master 
volume of any SAM output).
The card is routed pretty strange: the 2channel codec output is 
re-sampled and this digital signal is fed into the SAM device for 
further processing. From it can be output to 2 stereo pairs of outputs 
(ie 4 mono). But there are also 6 other mono inputs that are routed 
directly to the SAM device, and can be HW monitored on the SAM's outputs.

To make things even more complex: the digital stereo signal is 
multiplexed with an SPDIF input and two other mono inputs. You can 
choose which one you want (only one).

I'd like the codec mixer separate from the other controls, as this 
reflects internal structure best. Apart from that, the codec controls 
are rarely used, because I always use the SAM channels which are better 
quality.

Thanks,

Pieter



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Re: building a mixer

[Takashi Iwai]

At Tue, 28 Jan 2003 00:45:55 +0100,
Pieter Palmers wrote:
> 
> Hi all,
> 
> is it possible to support multiple mixers in one card?

no, on ALSA 0.9.0, there is only one control interface per card.

> I have the following situation:
> The card consists of a Maestro2E PCI controller with AC97 codec. On the 
> expansion port of the maestro is a SAM9707 device. I'd like separate 
> mixers for the AC97 and the SAM, because the control names can be very 
> confusing otherwise (i.e. Master volume of Codec does not change Master 
> volume of any SAM output).

it's possible to give the index value to the control element, so  that
the elements with the same name can coexist.

it's also possible to extend the existing API, of course, but i don't
think it's the best solution.
what we really need is a card-specific mixer application.  then you
can arrange the appearance more reasonably. 

i think either an external database giving the mixer topology or a
script-based mixer GUI which runs different scripts for each card will
be necessary.


Takashi


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Re: building a mixer

[Uros Bizjak]

Pieter Palmers wrote:

> is it possible to support multiple mixers in one card?
> I have the following situation:
> The card consists of a Maestro2E PCI controller with AC97 codec. On 
> the expansion port of the maestro is a SAM9707 device. I'd like 
> separate mixers for the AC97 and the SAM, because the control names 
> can be very confusing otherwise (i.e. Master volume of Codec does not 
> change Master volume of any SAM output).
> The card is routed pretty strange: the 2channel codec output is 
> re-sampled and this digital signal is fed into the SAM device for 
> further processing. From it can be output to 2 stereo pairs of outputs 
> (ie 4 mono). But there are also 6 other mono inputs that are routed 
> directly to the SAM device, and can be HW monitored on the SAM's outputs.
>
> To make things even more complex: the digital stereo signal is 
> multiplexed with an SPDIF input and two other mono inputs. You can 
> choose which one you want (only one).
>
> I'd like the codec mixer separate from the other controls, as this 
> reflects internal structure best. Apart from that, the codec controls 
> are rarely used, because I always use the SAM channels which are 
> better quality.

    Maybe the best approach is to treat ISIS card as two separate ones:
es1968 (maestro-2) and isis. However, es1968 code should be refactored
to es1968 toplevel module and es1968_lib midlevel code, which would be
shared with es1968and isis top modules.

    Now, someone could load isis, and this will load es1968_lib module
and silently set ac97 expansion port mixer to right value. If es1968
toplevel is loaded after that, it will detect es1968_lib module already
loaded in memory and use its code. However - as midlevel code is
actually accessing one chip, sharing issues should be resolved (don't
initialize already initialized chip, don't powerdown chip wich is used,
etc (use module usage heplers!)). I don't know if maestro's ISA
expansion pins could be accessed independently of its other functions,
but this way you could have two cards with two separate mixers: es1968
with its standard ac97 mixer and isis with its weird mixer.

    Uros.





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