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>
This commit is contained in:
Arnaud Mouiche 2016-05-03 14:13:58 +02:00 committed by Mark Brown
parent 0096b69396
commit d9f2a20287

View file

@ -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;