c06fb25d1f
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49 lines
1.7 KiB
Diff
49 lines
1.7 KiB
Diff
From a382d82b99a078f2ce65e78df9ba6db0d01c8ca3 Mon Sep 17 00:00:00 2001
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From: Phil Elwell <phil@raspberrypi.com>
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Date: Tue, 24 Sep 2024 20:34:54 +0100
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Subject: [PATCH 1285/1350] ASoC: bcm2835-i2s: Set the PERIOD_BYTES min to 256
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Commit [1] set the minimum PERIOD_BYTES value to the product of the DMA
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burst size and 8. For the I2S interface on BCM2835 that equates to 16
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where it used to be 256. ffmpeg uses the minimum value as its preferred
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value, leading to many, many very small periods, which affects
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performance and leads to complaints about DTS timestamps.
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Restore the previous behaviour and performance by making the bcm2835-i2s
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driver set a minimum PERIOD_BYTES value of 256.
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Link: https://github.com/raspberrypi/linux/issues/5709
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[1] 300689fb04b3 ("ASoC: soc-generic-dmaengine-pcm: set
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period_bytes_min based on maxburst")
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Signed-off-by: Phil Elwell <phil@raspberrypi.com>
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---
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sound/soc/bcm/bcm2835-i2s.c | 8 ++++++++
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1 file changed, 8 insertions(+)
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--- a/sound/soc/bcm/bcm2835-i2s.c
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+++ b/sound/soc/bcm/bcm2835-i2s.c
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@@ -619,6 +619,10 @@ static int bcm2835_i2s_prepare(struct sn
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struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
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uint32_t cs_reg;
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+ snd_pcm_hw_constraint_minmax(substream->runtime,
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+ SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 256,
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+ ~0);
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+
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/*
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* Clear both FIFOs if the one that should be started
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* is not empty at the moment. This should only happen
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@@ -700,6 +704,10 @@ static int bcm2835_i2s_startup(struct sn
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/* Should this still be running stop it */
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bcm2835_i2s_stop_clock(dev);
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+ snd_pcm_hw_constraint_minmax(substream->runtime,
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+ SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
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+ 256, ~0);
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+
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/* Enable PCM block */
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regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG,
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BCM2835_I2S_EN, BCM2835_I2S_EN);
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