Commit d9f2a202 authored May 03, 2016 by Arnaud Mouiche Committed by Mark Brown May 13, 2016

ASoC: fsl_ssi: Fix samples being dropped at Playback startup



If the capture is already running while playback is started, it is highly
probable (>80% in a 8 channels scenario) that samples are lost between
the DMA and TX fifo.

The reason is that SIER.TDMAE is set before STCR.TFEN0, leaving a time
window where the FIFO doesn't receive the samples written by the DMA.

This particular case happened only if capture is already enabled as
SCR.SSIEN is already set at the playback startup instant.

Signed-off-by: Arnaud Mouiche <arnaud.mouiche@invoxia.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Tested-by: Caleb Crome <caleb@crome.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

parent 0096b693

sound/soc/fsl/fsl_ssi.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -475,9 +475,9 @@ static void fsl_ssi_config(struct fsl_ssi_private *ssi_private, bool enable,
		* (online configuration)
		*/
		if (enable) {
		regmap_update_bits(regs, CCSR_SSI_SIER, vals->sier, vals->sier);
		regmap_update_bits(regs, CCSR_SSI_SRCR, vals->srcr, vals->srcr);
		regmap_update_bits(regs, CCSR_SSI_STCR, vals->stcr, vals->stcr);
		regmap_update_bits(regs, CCSR_SSI_SIER, vals->sier, vals->sier);
		} else {
		u32 sier;
		u32 srcr;

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