If the playback and capture of the same McASP is connected to different
dai link (non duplex PCM links, like with pcm3168a codec) then there is
a high probability of race between the two direction leaving McASP in a
confused state.
Protect the hw_params() with a mutex to make sure that this is not
happening.
The concurrent execution of hw_params for capture and playback can be
easily triggered with custom .asoundrc file (for pcm3168a codec):
pcm.dmixed8 {
type dmix
ipc_key 2048
ipc_perm 0666
slave {
pcm "hw:0,0"
format S24_LE
channels 8
rate 96000
}
bindings {
0 0
1 1
2 2
3 3
4 4
5 5
6 6
7 7
}
}
pcm.cpb-headset-1 {
type plug
slave.pcm dmixed8
hint {
show on
description "Headset 1 jack"
}
ttable.0.0 1
ttable.1.4 1
}
pcm.dsnooped6 {
type dsnoop
ipc_key 2049
ipc_perm 0666
slave {
pcm "hw:0,1"
format S24_LE
channels 6
rate 96000
}
bindings {
0 0
1 1
2 2
3 3
4 4
5 5
}
}
pcm.cpb-mic-1 {
type plug
slave.pcm "dsnooped6"
hint {
show on
description "Microphone 1 jack"
}
ttable.0.0 1
ttable.1.3 1
}
Then running:
arecord -D cpb-mic-1 -f S24_LE -c2 -r48000 | aplay -D cpb-headset-1 -f S24_LE -c2 -r48000
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
---
sound/soc/ti/davinci-mcasp.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/sound/soc/ti/davinci-mcasp.c b/sound/soc/ti/davinci-mcasp.c
index 7aa3c32e4a49..fe7a0b3572e2 100644
--- a/sound/soc/ti/davinci-mcasp.c
+++ b/sound/soc/ti/davinci-mcasp.c
@@ -111,6 +111,7 @@ struct davinci_mcasp {
u32 channels;
int max_format_width;
u8 active_serializers[2];
+ struct mutex mutex;
#ifdef CONFIG_GPIOLIB
struct gpio_chip gpio_chip;
@@ -1169,6 +1170,8 @@ static int davinci_mcasp_hw_params(struct snd_pcm_substream *substream,
int period_size = params_period_size(params);
int ret;
+ mutex_lock(&mcasp->mutex);
+
switch (params_format(params)) {
case SNDRV_PCM_FORMAT_U8:
case SNDRV_PCM_FORMAT_S8:
@@ -1197,12 +1200,13 @@ static int davinci_mcasp_hw_params(struct snd_pcm_substream *substream,
default:
printk(KERN_WARNING "davinci-mcasp: unsupported PCM format");
- return -EINVAL;
+ ret = -EINVAL;
+ goto out;
}
ret = davinci_mcasp_set_dai_fmt(cpu_dai, mcasp->dai_fmt);
if (ret)
- return ret;
+ goto out;
/*
* If mcasp is BCLK master, and a BCLK divider was not provided by
@@ -1223,7 +1227,7 @@ static int davinci_mcasp_hw_params(struct snd_pcm_substream *substream,
ret = mcasp_common_hw_param(mcasp, substream->stream,
period_size * channels, channels);
if (ret)
- return ret;
+ goto out;
if (mcasp->op_mode == DAVINCI_MCASP_DIT_MODE)
ret = mcasp_dit_hw_param(mcasp, params_rate(params));
@@ -1232,7 +1236,7 @@ static int davinci_mcasp_hw_params(struct snd_pcm_substream *substream,
channels);
if (ret)
- return ret;
+ goto out;
davinci_config_channel_size(mcasp, word_length);
@@ -1242,7 +1246,10 @@ static int davinci_mcasp_hw_params(struct snd_pcm_substream *substream,
mcasp->max_format_width = word_length;
}
- return 0;
+out:
+ mutex_unlock(&mcasp->mutex);
+
+ return ret;
}
static int davinci_mcasp_trigger(struct snd_pcm_substream *substream,
@@ -2335,6 +2342,8 @@ static int davinci_mcasp_probe(struct platform_device *pdev)
if (ret)
return -EINVAL;
+ mutex_init(&mcasp->mutex);
+
ret = devm_snd_soc_register_component(&pdev->dev,
&davinci_mcasp_component,
&davinci_mcasp_dai[pdata->op_mode], 1);
--
Peter
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
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