max98357a_daiops_trigger() is possible to be called in atomic context if
the .nonatomic flag is equal to 0 in the DAI links.
When cancel_delayed_work_sync() in max98357a_daiops_trigger() is called
in atomic context, kernel emits the following message: "BUG: sleeping
function called from invalid context".
According to the DT binding document, value less than or equal to 5ms of
sdmod-delay should be sufficient to avoid the pop noise. Use mdelay
(i.e. busy loop) for such low delay should be acceptable.
Fixes: cec5b01f8f1c ("ASoC: max98357a: avoid speaker pop when playback
startup")
Signed-off-by: Tzung-Bi Shih <tzungbi@xxxxxxxxxx>
---
Hi,
Not sure whether this fix is acceptable or not. Because in the document
"timers-howto.txt", it states "In general, use of mdelay is discouraged
and code should be refactored to allow for the use of msleep."
sound/soc/codecs/max98357a.c | 25 ++++---------------------
1 file changed, 4 insertions(+), 21 deletions(-)
diff --git a/sound/soc/codecs/max98357a.c b/sound/soc/codecs/max98357a.c
index 6f0e28f903bf..16313b973eaa 100644
--- a/sound/soc/codecs/max98357a.c
+++ b/sound/soc/codecs/max98357a.c
@@ -20,20 +20,10 @@
#include <sound/soc-dapm.h>
struct max98357a_priv {
- struct delayed_work enable_sdmode_work;
struct gpio_desc *sdmode;
unsigned int sdmode_delay;
};
-static void max98357a_enable_sdmode_work(struct work_struct *work)
-{
- struct max98357a_priv *max98357a =
- container_of(work, struct max98357a_priv,
- enable_sdmode_work.work);
-
- gpiod_set_value(max98357a->sdmode, 1);
-}
-
static int max98357a_daiops_trigger(struct snd_pcm_substream *substream,
int cmd, struct snd_soc_dai *dai)
{
@@ -46,14 +36,12 @@ static int max98357a_daiops_trigger(struct snd_pcm_substream *substream,
case SNDRV_PCM_TRIGGER_START:
case SNDRV_PCM_TRIGGER_RESUME:
case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
- queue_delayed_work(system_power_efficient_wq,
- &max98357a->enable_sdmode_work,
- msecs_to_jiffies(max98357a->sdmode_delay));
+ mdelay(max98357a->sdmode_delay);
+ gpiod_set_value(max98357a->sdmode, 1);
break;
case SNDRV_PCM_TRIGGER_STOP:
case SNDRV_PCM_TRIGGER_SUSPEND:
case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
- cancel_delayed_work_sync(&max98357a->enable_sdmode_work);
gpiod_set_value(max98357a->sdmode, 0);
break;
}
@@ -112,30 +100,25 @@ static int max98357a_platform_probe(struct platform_device *pdev)
int ret;
max98357a = devm_kzalloc(&pdev->dev, sizeof(*max98357a), GFP_KERNEL);
-
if (!max98357a)
return -ENOMEM;
max98357a->sdmode = devm_gpiod_get_optional(&pdev->dev,
"sdmode", GPIOD_OUT_LOW);
-
if (IS_ERR(max98357a->sdmode))
return PTR_ERR(max98357a->sdmode);
ret = device_property_read_u32(&pdev->dev, "sdmode-delay",
&max98357a->sdmode_delay);
-
if (ret) {
max98357a->sdmode_delay = 0;
dev_dbg(&pdev->dev,
- "no optional property 'sdmode-delay' found, default: no delay\n");
+ "no optional property 'sdmode-delay' found, "
+ "default: no delay\n");
}
dev_set_drvdata(&pdev->dev, max98357a);
- INIT_DELAYED_WORK(&max98357a->enable_sdmode_work,
- max98357a_enable_sdmode_work);
-
return devm_snd_soc_register_component(&pdev->dev,
&max98357a_component_driver,
&max98357a_dai_driver, 1);
--
2.22.0.410.gd8fdbe21b5-goog
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