On Fri, Oct 30, 2015 at 09:29:02AM +0100, arnaud.mouiche@xxxxxxxxxxx wrote: > At imx50 age, I remember one workaround was to fill the fifo > manually, writing directly a number of samples (equal to the number > of slots for one frame to keep the synchronization), and then, > enable the TMDAE. > This just allow to not have to wait an undefined period of time for > the DMA to be ready. > But, on the other hand, if the time to wait the DMA is short enough, > it should not be an issue. Nice input. This reminds me of the zero-filling step inside the ESAI startup procedure: case SNDRV_PCM_TRIGGER_START: case SNDRV_PCM_TRIGGER_RESUME: case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: regmap_update_bits(esai_priv->regmap, REG_ESAI_xFCR(tx), ESAI_xFCR_xFEN_MASK, ESAI_xFCR_xFEN); /* Write initial words reqiured by ESAI as normal procedure */ for (i = 0; tx && i < channels; i++) regmap_write(esai_priv->regmap, REG_ESAI_ETDR, 0x0); regmap_update_bits(esai_priv->regmap, REG_ESAI_xCR(tx), tx ? ESAI_xCR_TE_MASK : ESAI_xCR_RE_MASK, tx ? ESAI_xCR_TE(pins) : ESAI_xCR_RE(pins)); break; It's exactly the same thing to prevent underrun. This might be a reasonable alternative option due to no polling overhead and timeout handling. Thanks Nicolin _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
