[alsa-devel] EMU 1212 - 16 capture channels - patch

[dustin at seznam.cz]

Hello,

Here is the patch increasing number of capture channels from 8 to 16. In this patch the unused PCMs are not removed yet, I have not been able to test thoroughly to confirm they are 100% sure useless.

As a next project, I would like to try to raise playback resolution from the current 16bits to 24 (32) bits, using audigy DSP instructions, inversion of the convert32to2x16 function. I would really appreciate comments and suggestions from experts on this card regarding feasibility and possible caveats.

Patch description:

* adding 8 more 32-bit capture channels (total of 16) for emu1010 cards
* adding some code comments and card details description

Signed-off-by: Pavel Hofman <dustin at seznam.cz>


Thans a lot,

Pavel.

>  > 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.
>  
>  
>  thanks,
>  
>  Takashi
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