On Sat, Jan 28, 2017 at 12:35:45AM +0100, Sergej Sawazki wrote:
> Do not apply rate constraints in the startup() callback. The machine driver
> can change the sysclk and hence the supported frame rates in its hw_params().
> This callback is unneeded since commit e369bd006fd6 ("ASoC: wm8741: Allow
> master clock switching").
>
> Signed-off-by: Sergej Sawazki <ce3a@xxxxxx>
> ---
> sound/soc/codecs/wm8741.c | 15 ---------------
> 1 file changed, 15 deletions(-)
>
> diff --git a/sound/soc/codecs/wm8741.c b/sound/soc/codecs/wm8741.c
> index b8c1940..d6e540a 100644
> --- a/sound/soc/codecs/wm8741.c
> +++ b/sound/soc/codecs/wm8741.c
> @@ -176,20 +176,6 @@ static const struct snd_pcm_hw_constraint_list constraints_36864 = {
> .list = rates_36864,
> };
>
> -static int wm8741_startup(struct snd_pcm_substream *substream,
> - struct snd_soc_dai *dai)
> -{
> - struct snd_soc_codec *codec = dai->codec;
> - struct wm8741_priv *wm8741 = snd_soc_codec_get_drvdata(codec);
> -
> - if (wm8741->sysclk)
> - snd_pcm_hw_constraint_list(substream->runtime, 0,
> - SNDRV_PCM_HW_PARAM_RATE,
> - wm8741->sysclk_constraints);
> -
> - return 0;
> -}
> -
This function should not be removed it is performing a useful
function. If a sysclk has already been configured by the machine
driver then we should inform user-space of the rates we can
support from that clock. Without this that information is not
available to user-space, so instead of user-space being able to
resample appropriately it would just error out from hw_params.
Are you perhaps missing a call to clear the sysclk from your
machine driver? Usually a dai_set_sysclk call with a rate of
zero, also I find if it is a machine driver supporting multiple
rates you are best to use ignore_pmdown_time on the DAI link,
assuming the devices don't have long bring up times.
Thanks,
Charles
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