Re: [OT] ALSA userspace API complexity

Stefan Smietanowski
2006-01-06T15:03:26Z

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Hannu Savolainen wrote:
> On Thu, 5 Jan 2006, Lee Revell wrote:
>
>
>>On Fri, 2006-01-06 at 01:06 +0200, Hannu Savolainen wrote:
>>
>>>We have not received any single bug report that is caused
>>>by the concept of kernel mixing.
>>>Kernel mixing is not rocket science. All you need to do is picking a
>>>sample from the output buffers of each of the applications, sum them
>>>together (with some volume scaling) and feed the result to the
>>>physical
>>>device.
>>
>>Hey, interesting, this is exactly what dmix does in userspace. And we
>>have not seen any bug reports caused by the concept of userspace mixing
>>(just implementation bugs like any piece of software).
>
> Having dmix working in user space doesn't prove that kernel level mixing
> is evil. This was the original topic.

Wasn't there a thread a few years ago (3-5?) about sound mixing in the
kernel?

I've tried searching for it but have been unsuccessful so I could be
remembering wrong.

I can't remember if it was about OSS, ALSA or anything else but I
believe the conclusion was that sound mixing does NOT belong in the
kernel and SHOULD be done in userspace. I have a faint memory of that
being written by Alan Cox, but since it was a while ago I could very
well be mistaken there (too?).

// Stefan

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