[alsa-devel] WM8731 using I2S on omap3 McBSP2 issues

Peter Ujfalusi peter.ujfalusi at nokia.com
Tue Sep 29 10:43:17 CEST 2009

On Tuesday 29 September 2009 00:15:10 ext Rick Bronson wrote:
> Peter,
>   I'm getting a XUNDFLSTAT (indicates a real underflow condition) and
> XEMPTYEOF (Transmit buffer empty at end of frame) in
> MCBSPLP_IRQSTATUS_REG.  Does this tell you anything?

Hmm, this actually means that the DMA is not filling the McBSP buffer.
Since there is no data written in the McBSP buffer, it is shifting out 0 which 
is what you have observed on the DX line (goes low for the duration of aplay).

I have used McBSP as master on 2.6.28 kernel and I can not recall any big 
changes regarding to OMAP McBSP/DMA in between 28 and 29, so I'm a bit puzzled 
on this...

>   Rick


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