2016-12-02 10:50:26 +00:00
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From e27e038a64e9a3499f76e9581ea67b4b81a33555 Mon Sep 17 00:00:00 2001
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2016-04-24 11:03:39 +00:00
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From: Phil Elwell <phil@raspberrypi.org>
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Date: Thu, 21 Apr 2016 15:44:14 +0100
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2016-09-10 12:54:26 +00:00
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Subject: [PATCH] bcm2835-i2s: Reduce the TX DREQ threshold
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2016-04-24 11:03:39 +00:00
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TX FIFO overrun is thought to be the cause of channel swapping, so
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reducing the DREQ threshold seems reasonable and appears to be
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effective.
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See: https://github.com/raspberrypi/linux/issues/1417
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Signed-off-by: Phil Elwell <phil@raspberrypi.org>
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---
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sound/soc/bcm/bcm2835-i2s.c | 21 ++++++++++++++-------
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1 file changed, 14 insertions(+), 7 deletions(-)
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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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@@ -555,15 +555,22 @@ static int bcm2835_i2s_hw_params(struct
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/* Setup the DMA parameters */
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regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG,
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- BCM2835_I2S_RXTHR(1)
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- | BCM2835_I2S_TXTHR(1)
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- | BCM2835_I2S_DMAEN, 0xffffffff);
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+ BCM2835_I2S_RXTHR(3)
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+ | BCM2835_I2S_TXTHR(3)
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+ | BCM2835_I2S_DMAEN,
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+ BCM2835_I2S_RXTHR(1)
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+ | BCM2835_I2S_TXTHR(1)
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+ | BCM2835_I2S_DMAEN);
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regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_DREQ_A_REG,
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- BCM2835_I2S_TX_PANIC(0x10)
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- | BCM2835_I2S_RX_PANIC(0x30)
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- | BCM2835_I2S_TX(0x30)
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- | BCM2835_I2S_RX(0x20), 0xffffffff);
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+ BCM2835_I2S_TX_PANIC(0x7f)
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+ | BCM2835_I2S_RX_PANIC(0x7f)
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+ | BCM2835_I2S_TX(0x7f)
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+ | BCM2835_I2S_RX(0x7f),
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+ BCM2835_I2S_TX_PANIC(0x10)
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+ | BCM2835_I2S_RX_PANIC(0x30)
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+ | BCM2835_I2S_TX(0x20)
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+ | BCM2835_I2S_RX(0x20));
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/* Clear FIFOs */
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bcm2835_i2s_clear_fifos(dev, true, true);
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