On Fri, 02 Nov 2018 08:30:47 +0100,
Jenny TC wrote:
>
> Some DMICs require a delay as defined in the DMIC data sheet to complete
> DMIC mode transitions. DMIC may enter a bad state if the clock is stopped
> before successful mode transition. To handle this, a delay is introduced
> in the STOP STREAM to ensure the clock is running for the mode switch delay
> duration. A module parameter is introduced to pass the delay as a module
> parameter.
>
> Signed-off-by: Sathyanarayana Nujella <sathyanarayana.nujella@xxxxxxxxx>
> Signed-off-by: Jairaj Arava <jairaj.arava@xxxxxxxxx>
> Signed-off-by: Harsha Priya <harshapriya.n@xxxxxxxxx>
> ---
> sound/soc/codecs/dmic.c | 31 +++++++++++++++++++++++++++++++
> 1 file changed, 31 insertions(+)
>
> diff --git a/sound/soc/codecs/dmic.c b/sound/soc/codecs/dmic.c
> index 8c4926d..0527bc2 100644
> --- a/sound/soc/codecs/dmic.c
> +++ b/sound/soc/codecs/dmic.c
> @@ -30,9 +30,35 @@
> #include <sound/soc.h>
> #include <sound/soc-dapm.h>
>
> +static int modeswitch_delay_ms;
> +module_param(modeswitch_delay_ms, uint, 0644);
signed or unsigned?
> struct dmic {
> struct gpio_desc *gpio_en;
> int wakeup_delay;
> + /* Delay after DMIC mode switch */
> + int modeswitch_delay_ms;
> +};
> +
> +int dmic_daiops_trigger(struct snd_pcm_substream *substream,
> + int cmd, struct snd_soc_dai *dai)
> +{
> + struct snd_soc_component *component = dai->component;
> + struct dmic *dmic = snd_soc_component_get_drvdata(component);
> +
> + switch (cmd) {
> + case SNDRV_PCM_TRIGGER_STOP:
> + if (dmic->modeswitch_delay_ms)
> + mdelay(dmic->modeswitch_delay_ms);
You need to have a value sanity check either at execution time or at
initialization time. The current code allows user to stall for a
quite long time by passing some bad value via module option.
thanks,
Takashi
_______________________________________________
Alsa-devel mailing list
Alsa-devel@xxxxxxxxxxxxxxxx
http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
