Dong Aisheng <b29396@xxxxxxxxxxxxx> writes:
> From: Dong Aisheng <dong.aisheng@xxxxxxxxxx>
>
> Currently we directly call a clock_enable in trigger function without
> a clk_prepare as pair first.
> This will cause system hang immediately when run capture because
> the clock was not prepared(playback does not hang because the clock was
> prepared already by get_mclk before), a warning message in clock framework
> may cause a deadlock to reclaim clock lock (see: pl011_console_write).
>
> Here we prepare clock first in hw_param, then enable it in trigger
> function to guarantee the balance.
>
> Cc: Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
> Cc: Liam Girdwood <lrg@xxxxxx>
> Cc: Wolfram Sang <w.sang@xxxxxxxxxxxxxx>
> Cc: Shawn Guo <shawn.guo@xxxxxxxxxx>
> Signed-off-by: Dong Aisheng <dong.aisheng@xxxxxxxxxx>
> ---
> sound/soc/mxs/mxs-saif.c | 10 ++++++++++
> 1 files changed, 10 insertions(+), 0 deletions(-)
>
> diff --git a/sound/soc/mxs/mxs-saif.c b/sound/soc/mxs/mxs-saif.c
> index aba71bf..fdbb36a 100644
> --- a/sound/soc/mxs/mxs-saif.c
> +++ b/sound/soc/mxs/mxs-saif.c
> @@ -394,9 +394,14 @@ static int mxs_saif_hw_params(struct snd_pcm_substream *substream,
> struct snd_soc_dai *cpu_dai)
> {
> struct mxs_saif *saif = snd_soc_dai_get_drvdata(cpu_dai);
> + struct mxs_saif *master_saif;
> u32 scr, stat;
> int ret;
>
> + master_saif = mxs_saif_get_master(saif);
> + if (!master_saif)
> + return -EINVAL;
> +
> /* mclk should already be set */
> if (!saif->mclk && saif->mclk_in_use) {
> dev_err(cpu_dai->dev, "set mclk first\n");
> @@ -420,6 +425,11 @@ static int mxs_saif_hw_params(struct snd_pcm_substream *substream,
> return ret;
> }
>
> + /* prepare clk in hw_param, enable in trigger */
> + clk_prepare(saif->clk);
> + if (saif != master_saif)
> + clk_prepare(master_saif->clk);
> +
> scr = __raw_readl(saif->base + SAIF_CTRL);
>
> scr &= ~BM_SAIF_CTRL_WORD_LENGTH;
> --
This is missing a matching clk_unprepare() call.
--
Måns Rullgård
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