Re: Prodigy 7.1 driver update [snd-ice1724]

[Takashi Iwai <tiwai@suse.de>]

At Mon, 24 Nov 2003 12:53:47 -0500,
Apostolos Dimitromanolakis wrote:
> 
> Hi,
> 
>   here's the new revision of the Audiotrak Prodigy 7.1 driver.  The 
> driver now initializes correctly for the 24.576Mhz crystal and also I 
> have added some more controls for adc oversampling ratio (in theory 
> should be changed automatically to 64x at 96Khz sampling rate) and dac 
> de-emphasis.
> 
>   The initialization sequence of the WM8770 has been modified to reduce 
> the pop noise at startup (now it's almost nono-existant). Also the 
> volume control updates now only at zero cross automatically to reduce 
> again the noise when changing volumes. I think the aureon driver should 
> also benefit from these two so I include a patch for the aureon.c too.

thanks, applied to cvs with minor modifications.
i changed the put callback to compare with the old value to avoid the
no necessary performance.  too often i2c transfer can be problematic
when a crazy mixer apps accesses to mixer elements.


>  Finally there is some misconception in the aureon & prodigy drivers: 
> the codec chip does not have a Master control as it appears at the 
> mixer. Instead the master control just updates the 8 volume controls of 
> the individual DAC at the same time. Probably the best way is to add a 
> virtual master control (ie that we update the volumes of the dac with  
> <master attenuation> + <specific channel attenuation> ).

well, such a thing should be done on user-space rather than on
kernel.  let's postpone this until the new highlevel mixer functions
become available.

> 
> As I wrote some days ago, the default buffer/period rates that 
> alsarecord uses at 44.1KHz and lower sampling , locks hard the kernel. 
> Have no idea what is it/how to fix it whatsoever.

hmm, could be the mismatch of cristal rate?
i don't find out the critical path in the driver yet.


Takashi


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