[alsa-devel] [PATCH 3/3] ASoC: omap-mcbsp: Add period size protection mode

Mark Brown broonie at opensource.wolfsonmicro.com
Tue Mar 20 17:01:56 CET 2012

On Tue, Mar 20, 2012 at 01:13:41PM +0200, Peter Ujfalusi wrote:
> Certain application can experience underrun right after the playback start.
> This is caused by the McBSP FIFO/sDMA integration:
> The sDMA will push samples to the FIFO till it has threshold amount of free
> slots available in the FIFO. If the application picks period size which is
> smaller than the FIFO size, and it did not prepared multiple periods, or
> it did not set the start_threshold for the stream to cover the FIFO size
> the hw pointer will move forward, which is causing the underrun.

Acked-by: Mark Brown <broonie at opensource.wolfsonmicro.com>

though this should probably have the note about working around broken
applications from the cover letter in the changelog as with the
changelog alone it's really not apparent why we're doing this here as a
driver specific thing.
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