From a7f989cdcb11a8ff5bbb51a675e3662872b5dd55 Mon Sep 17 00:00:00 2001 From: Phil Elwell Date: Thu, 21 Apr 2016 15:44:14 +0100 Subject: [PATCH] bcm2835-i2s: Reduce the TX DREQ threshold TX FIFO overrun is thought to be the cause of channel swapping, so reducing the DREQ threshold seems reasonable and appears to be effective. See: https://github.com/raspberrypi/linux/issues/1417 Signed-off-by: Phil Elwell --- sound/soc/bcm/bcm2835-i2s.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) --- a/sound/soc/bcm/bcm2835-i2s.c +++ b/sound/soc/bcm/bcm2835-i2s.c @@ -555,15 +555,22 @@ static int bcm2835_i2s_hw_params(struct /* Setup the DMA parameters */ regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG, - BCM2835_I2S_RXTHR(1) - | BCM2835_I2S_TXTHR(1) - | BCM2835_I2S_DMAEN, 0xffffffff); + BCM2835_I2S_RXTHR(3) + | BCM2835_I2S_TXTHR(3) + | BCM2835_I2S_DMAEN, + BCM2835_I2S_RXTHR(1) + | BCM2835_I2S_TXTHR(1) + | BCM2835_I2S_DMAEN); regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_DREQ_A_REG, - BCM2835_I2S_TX_PANIC(0x10) - | BCM2835_I2S_RX_PANIC(0x30) - | BCM2835_I2S_TX(0x30) - | BCM2835_I2S_RX(0x20), 0xffffffff); + BCM2835_I2S_TX_PANIC(0x7f) + | BCM2835_I2S_RX_PANIC(0x7f) + | BCM2835_I2S_TX(0x7f) + | BCM2835_I2S_RX(0x7f), + BCM2835_I2S_TX_PANIC(0x10) + | BCM2835_I2S_RX_PANIC(0x30) + | BCM2835_I2S_TX(0x20) + | BCM2835_I2S_RX(0x20)); /* Clear FIFOs */ bcm2835_i2s_clear_fifos(dev, true, true);