[PATCH v5 04/11] ASoC: tegra20: spdif: Set FIFO trigger level
From: Dmitry Osipenko <digetx@gmail.com>
Date: 2021-12-17 17:58:36
Also in:
alsa-devel, linux-tegra, lkml
Subsystem:
sound, sound - soc layer / dynamic audio power management (asoc), the rest · Maintainers:
Jaroslav Kysela, Takashi Iwai, Liam Girdwood, Mark Brown, Linus Torvalds
FIFO trigger level must be bigger than or equal to the size of DMA burst, otherwise audio will be played x4 faster than it should be because part of the DMA data will be dropped on FIFO input buffer overflow. Acked-by: Thierry Reding <redacted> Signed-off-by: Dmitry Osipenko <digetx@gmail.com> --- sound/soc/tegra/tegra20_spdif.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/sound/soc/tegra/tegra20_spdif.c b/sound/soc/tegra/tegra20_spdif.c
index 57a6c576b91f..e45e371edc42 100644
--- a/sound/soc/tegra/tegra20_spdif.c
+++ b/sound/soc/tegra/tegra20_spdif.c@@ -69,6 +69,14 @@ static int tegra20_spdif_hw_params(struct snd_pcm_substream *substream, regmap_update_bits(spdif->regmap, TEGRA20_SPDIF_CTRL, mask, val); + /* + * FIFO trigger level must be bigger than DMA burst or equal to it, + * otherwise data is discarded on overflow. + */ + regmap_update_bits(spdif->regmap, TEGRA20_SPDIF_DATA_FIFO_CSR, + TEGRA20_SPDIF_DATA_FIFO_CSR_TX_ATN_LVL_MASK, + TEGRA20_SPDIF_DATA_FIFO_CSR_TX_ATN_LVL_TU4_WORD_FULL); + switch (params_rate(params)) { case 32000: spdifclock = 4096000;
--
2.33.1