linux-kernel - RE: [PATCH] ASoC: dapm: Fix the unpaired runtime

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Date:	Thu, 20 Dec 2012 06:37:26 +0000
From:	"Liu, Chuansheng" <chuansheng.liu@...el.com>
To:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
CC:	"lrg@...com" <lrg@...com>, "perex@...ex.cz" <perex@...ex.cz>,
	"tiwai@...e.de" <tiwai@...e.de>,
	"alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"Liu, Chuansheng" <chuansheng.liu@...el.com>
Subject: RE: [PATCH] ASoC: dapm: Fix the unpaired runtime_get/put cases



> -----Original Message-----
> From: Mark Brown [mailto:broonie@...nsource.wolfsonmicro.com]
> Sent: Wednesday, December 19, 2012 5:11 PM
> To: Liu, Chuansheng
> Cc: lrg@...com; perex@...ex.cz; tiwai@...e.de; alsa-devel@...a-project.org;
> linux-kernel@...r.kernel.org
> Subject: Re: [PATCH] ASoC: dapm: Fix the unpaired runtime_get/put cases
> 
> On Wed, Dec 19, 2012 at 06:36:37PM +0800, Chuansheng Liu wrote:
> 
> > But some devices has been set to STANDY bias directly during device probing,
> > such as cs42l73_probe():
> > cs42l73_set_bias_level(codec, SND_SOC_BIAS_STANDBY);
> 
> > Then it will cause runtime_get() not be called but laterly runtime_put() will
> > be called. Also found some other uppaired cases.
> 
> This is just a bug in the driver, if it's idle_bias_off then it really
> should be starting in _OFF or at the very least starting actually in
> _STANDBY (including taking the runtime reference) rather than partially
> in _STANDBY.
Thanks your pointing out. You are totally right.
Rechecked the related driver code, there is one place which starting from _STANDBY with idle_bias_off.
It should be the main reason of bringing unpaired issue.

Meanwhile, is it useful to add one warning there for that case?
After all, in probing, set the bias to _STANDBY even idle_bias_off == 1, and calling get_runtime_sync(), it
will let the code more obscure. So giving a warning there to indicate the driver:
it is not suggested that in probing, set the bias to _STANDBY even idle_bias_off == 1.

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 9c768bc..d6adaec 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -1102,6 +1102,8 @@ static int soc_probe_codec(struct snd_soc_card *card,
 
        if (driver->probe) {
                ret = driver->probe(codec);
+               WARN_ON(codec->dapm.idle_bias_off &&
+                       codec->dapm.bias_level != SND_SOC_BIAS_OFF);
                if (ret < 0) {
                        dev_err(codec->dev,
                                "ASoC: failed to probe CODEC %d\n", ret);
--
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