[alsa-devel] [PATCH] ASoC: Automatically set TDM if needed on pxa-ssp and allow frame width override when using TDM.

[Daniel Ribeiro]

Em Qua, 2009-06-10 às 19:44 +0800, Paul Shen escreveu:
> Seems the frame_width has no  such relations with sampe width, the
> sample width is defined on runtime by the audio files.
> Make a example sample with  paly a often used 16bit sample width
> stereo aduio file.

> When you play 16bit audio sample with  2*16 bit frame ,
>          frame   --|____________|------------------|_____________|---
>          data      --<======>-<======>-<======>-
>          here the datasize should be SSCR0_DataSize(16), the frame size is 32

No, the example above would be DataSize(32), SFRMWDTH(16). (LEFT_J?)

Or it could be DataSize(16) and 2 active TDM Slots.

But the point here is to not use SSCR0_MOD when its not needed
(sample * chn <= 32), we need to support real networked configurations,
set_tdm_slot() should only be called if you are really using network
mode. eg:

set_tdm_slots(3, 2) shouldn't ever be needed.

> also you can play 16bit audio sample with 2*32 frame,
>          frame
> --|_________________________|------------------------------------|____
>          data     --<======>-------------------<======>-------------------<==
>          here the datasize is also DataSize(16), but the frame size is 64.
> 
> Do I misunderstand you?

Sure you can waste bitclocks.. But we should try to only waste bitclocks
when it is really needed, eg for I2S. The patch is not considering I2S
yet.


-- 
Daniel Ribeiro
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