Status of VIA Envy24 audio controller

Konstantin Dimitrov kosio.dimitrov at
Mon Jul 24 13:35:43 UTC 2006

On 7/24/06, Alexander Leidinger <Alexander at> wrote:
> Quoting Konstantin Dimitrov <kosio.dimitrov at> (from Mon, 24
> Jul 2006 11:37:59 +0000):
> > during the last weekend i have some free time and decided to look
> through
> > the list of reported problems:
> In case there are some open PRs I would like to know the number of them...

i think there are no PRs,  Stefan and Nikolas reported the problems to the
freebsd-multimedia at

> 5) vchans don't work
> >
> > it is a feature, not a bug and it is really great feature, so should be
> > removed from the list with bugs. Envy24(1712) has very precise 36bit
> wide
> > hardware mixer, which is superior that vchans (software sound mixer in
> the
> > kernel). the driver supports Envy24(1712) hardware mixer, so up to 10
> > channels (5 stereo pairs) can be playback simultaneously and that is why
> no
> > software sound mixer (vchans) is needed.
> What if someone wants to play more than 5 stereo pairs at once?
> I agree that if an high quality feature like this is supported, it
> should be used. But I don't agree that we should not use vchans. If
> someone wants to use vchans, he should be able to use them (we can add
> a note into the man page regarding the hardware feature and the
> relative quality of it compared to vchans).

i agree that it is a good idea to be able to choose between the use of
vchans or build-in hardware mixer and maybe it's not properly implemented
like Ariff Abdullah mentioned, maybe Ariff will help for proper
implementation, i'm not enough familiar with newpcm, also all others Envy24
chips - 172x don't have build-in hardware mixer and volume support, so it is
great to hear that "8/16/24/32 sign/unsigned vchan/softpcmvol/ssrc does
exist" and maybe in that case vchans are much better choice and will remove
a lot of complexity and problems from the driver.

Regarding the use of the hardware feature: How do you make use of it
> in the driver? Do you allow the same stereo channel to get opened 5
> times and let the hardware handle everything?

as you know the author of the driver is Katsurajima Naoto and he is using
the following approach to achieve hardware mixing:
route all Envy24 DMA channels to the build-in hardware mixer and register 5
channels using "pcm_register" and "pcm_addchan" and every channel using
different Envy24 DMA channel.

> Alexander.
> --
> Kiss your keyboard goodbye!
>    Alexander @ PGP ID = B0063FE7
>       netchild @  : PGP ID = 72077137

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