linux-kernel - Re: [PATCH 3/3] ASoC: fsl_ssi: remove register defaults

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Message-ID: <20160111140038.GC6588@sirena.org.uk>
Date:	Mon, 11 Jan 2016 14:00:38 +0000
From:	Mark Brown <broonie@...nel.org>
To:	Fabio Estevam <festevam@...il.com>
Cc:	"Maciej S. Szmigiero" <mail@...iej.szmigiero.name>,
	"alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
	Timur Tabi <timur@...i.org>,
	Nicolin Chen <nicoleotsuka@...il.com>,
	Xiubo Li <Xiubo.Lee@...il.com>,
	Liam Girdwood <lgirdwood@...il.com>,
	"linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3] ASoC: fsl_ssi: remove register defaults

On Mon, Jan 11, 2016 at 10:10:56AM -0200, Fabio Estevam wrote:
> On Mon, Jan 11, 2016 at 10:04 AM, Fabio Estevam <festevam@...il.com> wrote:

> > [    2.526984] ------------[ cut here ]------------
> > [    2.531632] WARNING: CPU: 1 PID: 1 at kernel/locking/lockdep.c:2755
> > lockdep_trace_alloc+0xf4/0x124()

> This fixes the warning:

> --- a/sound/soc/fsl/fsl_ssi.c
> +++ b/sound/soc/fsl/fsl_ssi.c
> @@ -180,7 +180,6 @@ static const struct regmap_config fsl_ssi_regconfig = {
>         .volatile_reg = fsl_ssi_volatile_reg,
>         .precious_reg = fsl_ssi_precious_reg,
>         .writeable_reg = fsl_ssi_writeable_reg,
> -       .cache_type = REGCACHE_RBTREE,
>  };

> Is this the correct fix?

I suspect not, it looks like the driver is using the cache for
suspend/resume handling.  I've dropped the patch for now.  Either the
driver should explicitly write to the relevant registers outside of
interrupt context to ensure the cache entry exists or it should keep the
defaults and explicitly write them to hardware at startup to ensure
sync (the former is more likely to be safe).

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