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authorJohn Keeping <john@metanate.com>2018-01-08 16:01:04 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-02-17 13:21:17 +0100
commit76376783a453c6893d38266cbbaed9fc0d3b7f74 (patch)
tree9573f31ac4b2cba4653ba75367d881dec70b1110
parentf6741799aa5321c52a83ff5d9ce753165774d63c (diff)
ASoC: rockchip: i2s: fix playback after runtime resume
commit c66234cfedfc3e6e3b62563a5f2c1562be09a35d upstream. When restoring registers during runtime resume, we must not write to I2S_TXDR which is the transmit FIFO as this queues up a sample to be output and pushes all of the output channels down by one. This can be demonstrated with the speaker-test utility: for i in a b c; do speaker-test -c 2 -s 1; done which should play a test through the left speaker three times but if the I2S hardware starts runtime suspended the first sample will be played through the right speaker. Fix this by marking I2S_TXDR as volatile (which also requires marking it as readble, even though it technically isn't). This seems to be the most robust fix, the alternative of giving I2S_TXDR a default value is more fragile since it does not prevent regcache writing to the register in all circumstances. While here, also fix the configuration of I2S_RXDR and I2S_FIFOLR; these are not writable so they do not suffer from the same problem as I2S_TXDR but reading from I2S_RXDR does suffer from a similar problem. Fixes: f0447f6cbb20 ("ASoC: rockchip: i2s: restore register during runtime_suspend/resume cycle", 2016-09-07) Signed-off-by: John Keeping <john@metanate.com> Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--sound/soc/rockchip/rockchip_i2s.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/sound/soc/rockchip/rockchip_i2s.c b/sound/soc/rockchip/rockchip_i2s.c
index 974915cb4c4f..08bfee447a36 100644
--- a/sound/soc/rockchip/rockchip_i2s.c
+++ b/sound/soc/rockchip/rockchip_i2s.c
@@ -476,6 +476,7 @@ static bool rockchip_i2s_rd_reg(struct device *dev, unsigned int reg)
case I2S_INTCR:
case I2S_XFER:
case I2S_CLR:
+ case I2S_TXDR:
case I2S_RXDR:
case I2S_FIFOLR:
case I2S_INTSR:
@@ -490,6 +491,9 @@ static bool rockchip_i2s_volatile_reg(struct device *dev, unsigned int reg)
switch (reg) {
case I2S_INTSR:
case I2S_CLR:
+ case I2S_FIFOLR:
+ case I2S_TXDR:
+ case I2S_RXDR:
return true;
default:
return false;
@@ -499,6 +503,8 @@ static bool rockchip_i2s_volatile_reg(struct device *dev, unsigned int reg)
static bool rockchip_i2s_precious_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
+ case I2S_RXDR:
+ return true;
default:
return false;
}