Re: [LAU] No more PCI!

From: Clemens Ladisch <clemens@email-addr-hidden>
Date: Wed Jan 27 2010 - 09:59:08 EET

Pieter Palmers wrote:
> Talking about mixer controls: do you intend to expose all mixer controls

Yes.

> to ALSA,

x*y monitoring controls would suck in a 'normal' mixer application.

> or would a custom application still be the way to go for mixers?

Yes. In theory, it shouldn't be difficult to make the existing (if any)
custom mixer work with both drivers.

> Can ALSA handle mixer capabilities that change with changing device
> configurations?

Yes; mixer controls can be changed, created and destroyed at runtime.

>> Hotplugging and device aggregation should work just fine, although not
>> both together, i.e., ALSA doesn't allow changing the stream format while
>> the stream is running. Is this possible with FFADO+Jack?
>
> With the current version of FFADO this is not possible as bus resets are
> not handled properly. But there is no technical reason that prevents
> this. Jack ports can be created and destroyed at run-time, and that's
> all it takes.
>
> The major use-case I'm thinking of is where a user inadvertently unplugs
> the device. With current FFADO this is a show stopper, but I'd like to
> see a system that keeps running and restores everything once the device
> is re-attached.

If Jack cannot fix a xrun immediately by restarting, it dies. If the
device stays unplugged, waiting indefinitely for it to reappear would
make no sense. This cannot be handled without asking the user.

>>> So maybe you should worry more about the confusion that might cause...
>>
>> While potential users might disagree, I think more choice is better.
>
> Most likely users won't care as long as it works (at least that's how I
> look at things I didn't develop myself). The challenge will therefore be
> to ensure that both systems can co-exist.

I can see the bug report: "I started both Jack+firewire and some ALSA
program, but the output wasn't properly mixed." ;-)

Best regards,
Clemens
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Received on Wed Jan 27 12:15:03 2010

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