[alsa-devel] [RFC 3/4] OMAP3: McBSP: Add interface for transmit FIFO state query
lrg at slimlogic.co.uk
Tue Mar 2 14:58:04 CET 2010
On Tue, 2010-03-02 at 15:52 +0200, Eero Nurkkala wrote:
> On Tue, 2010-03-02 at 14:39 +0100, Ujfalusi Peter (Nokia-D/Tampere)
> > New function for reading the XBUFFSTAT register, which holds
> > the fill state of the transmit buffer on McBSP.
> > Signed-off-by: Peter Ujfalusi <peter.ujfalusi at nokia.com>
> > ---
> Reading the XBUFFSTAT register is by no means accurate.
> IIRC, it reports the buffer status incorrectly about 1/50 times
> on average (@ 48000khz); with simple math, it may be read during the DMA
> burst. Or is it guaranteed not being read during DMA transfer / have
> you otherwise verified the behavior?
I agree, I've also seen XBUFFSTAT giving complete garbage with mcbsp3.
Freelance Developer, SlimLogic Ltd
ASoC and Voltage Regulator Maintainer.
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