[alsa-devel] [PATCH 1/5] ASoC: fsl_asrc: use flat regmap cache

[Fabio Estevam]

Hi Marek,

On Mon, Sep 19, 2016 at 4:30 PM, Marek Vasut <marex at denx.de> wrote:
> Same as commit ce492b3b8f99cf9d2f807ec22d8805c996a09503
> Subject: drm/fsl-dcu: use flat regmap cache

Just one minor nit:

The most standard way to reference a commit is:
commit ce492b3b8f99 ("drm/fsl-dcu: use flat regmap cache")

Reviewed-by: Fabio Estevam <fabio.estevam at nxp.com>






> Using flat regmap cache instead of RB-tree to avoid the following
> lockdep warning on driver load:
> WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:2871 lockdep_trace_alloc+0x104/0x128
> DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))
>
> The RB-tree regmap cache needs to allocate new space on first
> writes. However, allocations in an atomic context (e.g. when a
> spinlock is held) are not allowed. The function regmap_write
> calls map->lock, which acquires a spinlock in the fast_io case.
> Since the driver uses MMIO, the regmap bus of type regmap_mmio
> is being used which has fast_io set to true.
>
> Signed-off-by: Marek Vasut <marex at denx.de>
> Cc: Fabio Estevam <fabio.estevam at nxp.com>
> Cc: Liam Girdwood <lgirdwood at gmail.com>
> Cc: Mark Brown <broonie at kernel.org>
> Cc: Nicolin Chen <nicoleotsuka at gmail.com>
> Cc: Timur Tabi <timur at tabi.org>
> Cc: Xiubo Li <Xiubo.Lee at gmail.com>
> ---
>  sound/soc/fsl/fsl_asrc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/sound/soc/fsl/fsl_asrc.c b/sound/soc/fsl/fsl_asrc.c
> index b7157ce..1d82f68 100644
> --- a/sound/soc/fsl/fsl_asrc.c
> +++ b/sound/soc/fsl/fsl_asrc.c
> @@ -726,7 +726,7 @@ static const struct regmap_config fsl_asrc_regmap_config = {
>         .readable_reg = fsl_asrc_readable_reg,
>         .volatile_reg = fsl_asrc_volatile_reg,
>         .writeable_reg = fsl_asrc_writeable_reg,
> -       .cache_type = REGCACHE_RBTREE,
> +       .cache_type = REGCACHE_FLAT,
>  };
>
>  /**
> --
> 2.9.3
>
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