diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.4/0303-bcm2835-i2s-Reduce-the-TX-DREQ-threshold.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.4/0303-bcm2835-i2s-Reduce-the-TX-DREQ-threshold.patch | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.4/0303-bcm2835-i2s-Reduce-the-TX-DREQ-threshold.patch b/target/linux/brcm2708/patches-4.4/0303-bcm2835-i2s-Reduce-the-TX-DREQ-threshold.patch new file mode 100644 index 0000000000..8cfcf79913 --- /dev/null +++ b/target/linux/brcm2708/patches-4.4/0303-bcm2835-i2s-Reduce-the-TX-DREQ-threshold.patch @@ -0,0 +1,48 @@ +From ddb9af17e2f52474d45c0afc04abc2af4510110e Mon Sep 17 00:00:00 2001 +From: Phil Elwell <phil@raspberrypi.org> +Date: Thu, 21 Apr 2016 15:44:14 +0100 +Subject: [PATCH 303/304] 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 <phil@raspberrypi.org> +--- + 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); |