[alsa-devel] Patch - Revo7.1 PCM Playback Switch

Takashi Iwai tiwai at suse.de
Mon May 21 17:56:43 CEST 2007

At Fri, 18 May 2007 22:53:50 +0200 (CEST),
dustin at seznam.cz wrote:
> Hello Takashi,
> I have attached a patch to support mute for front channels of
> M-Audio Revolution 7.1 (the DAC AK4381 features a mute bit). 
> Signed-off-by: Pavel Hofman <dustin at seznam.cz>

Applied to HG tree.  Thanks.

> Please could I ask you for your opinion on the following issue (so
> far no response): 
> I am working together with Ctirad on supporting more capture
> channels in E-MU1212. So far we have managed to increase the number
> of channels from the default of 8 to 16 (A_FXWC2 = 0xffffffff, added
> new snd_emu10k1_audigy_dsp_convert_32_to_2x16 calls in
> emufx.c). There is still a number of issues to solve but the 16
> channel capture already works fine. 
> I would like to get your opinion on the form of adding this support
> to the module. The options are either hard-coding the 16 capture
> channels into the code, assuming that users would prefer as many
> channels as possible and do the routing in jack, or introducing a
> module parameter emu1010-capture-channels (range e.g. 1 to 16 -
> untested yet) and leaving the default number at the existing 8. 

I'm for the fixed number 16, as Lee already suggested.
It's simpler, and no one would complain that he has too many :)

> Furthermore, the PCMs other than efx seem to be of no use for the
> EMU-1x1x models, probably fairly confusing for new users. Would you
> find it OK, if they were removed for this specific card (if
> (emu->card_capabilities->emu1010)), keeping only the playback and
> capture PCM id 2?

I think it's OK to remove them if they are really useless.
But, make sure to change the card->driver name if you do this.
Otherwise the same configuration as Audigy2 or whatever will be used
and it may result in accessing non-existing devices.

> Thanks a lot for your suggestions. Based on them, I will prepare the
> patch (with comments on what we found out about the card - it is a
> pitty that the driver has almost no big-picture comments on the
> supported cards' specifics, making new developers spend a number of
> long nights going through the nontrivial code and guessing). 

The patches will be definitely appreciated.



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