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From: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
To: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: linuxarm@huawei.com, mauro.chehab@huawei.com,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	linux-kernel@vger.kernel.org, linux-media@vger.kernel.org
Subject: Re: [PATCH 25/25] media: i2c: ccs-core: fix pm_runtime_get_sync() usage count
Date: Wed, 5 May 2021 12:57:00 +0200	[thread overview]
Message-ID: <20210505125700.4a7584ca@coco.lan> (raw)
In-Reply-To: <20210505103409.GN3@paasikivi.fi.intel.com>

Em Wed, 5 May 2021 13:34:09 +0300
Sakari Ailus <sakari.ailus@linux.intel.com> escreveu:

> Hi Mauro,
> 
> Thanks for the patch.
> 
> On Wed, May 05, 2021 at 11:42:15AM +0200, Mauro Carvalho Chehab wrote:
> > The pm_runtime_get_sync() internally increments the
> > dev->power.usage_count without decrementing it, even on errors.
> > 
> > There is a bug at ccs_pm_get_init(): when this function returns
> > an error, the stream is not started, and RPM usage_count
> > should not be incremented. However, if the calls to
> > v4l2_ctrl_handler_setup() return errors, it will be kept
> > incremented.
> > 
> > At ccs_suspend() the best is to replace it by the new
> > pm_runtime_resume_and_get(), introduced by:
> > commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
> > in order to properly decrement the usage counter automatically,
> > in the case of errors.
> > 
> > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>  
> 
> Could you add Fixes: line and Cc: stable?

Sure. See the fixes one enclosed.

> The patch that breaks this is 96e3a6b92f23a .
> 
> It would be better to fix the bug first so the patch to the stable trees
> doesn't need special handling.
> 
> > ---
> >  drivers/media/i2c/ccs/ccs-core.c | 39 ++++++++++++++++++++------------
> >  1 file changed, 24 insertions(+), 15 deletions(-)
> > 
> > diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c
> > index b05f409014b2..04c3ab9e37b4 100644
> > --- a/drivers/media/i2c/ccs/ccs-core.c
> > +++ b/drivers/media/i2c/ccs/ccs-core.c
> > @@ -1880,21 +1880,33 @@ static int ccs_pm_get_init(struct ccs_sensor *sensor)
> >  	struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
> >  	int rval;
> >  
> > +	/*
> > +	 * It can't use pm_runtime_resume_and_get() here, as the driver
> > +	 * relies at the returned value to detect if the device was already
> > +	 * active or not.
> > +	 */
> >  	rval = pm_runtime_get_sync(&client->dev);
> > -	if (rval < 0) {
> > -		pm_runtime_put_noidle(&client->dev);
> > +	if (rval < 0)
> > +		goto error;
> >  
> > -		return rval;
> > -	} else if (!rval) {
> > -		rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->
> > -					       ctrl_handler);
> > -		if (rval)
> > -			return rval;
> > +	/* Device was already active, so don't set controls */
> > +	if (rval == 1)
> > +		return 0;
> >  
> > -		return v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
> > -	}
> > +	/* Restore V4L2 controls to the suspended device */
> > +	rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->ctrl_handler);
> > +	if (rval)
> > +		goto error;
> >  
> > +	rval = v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
> > +	if (rval)
> > +		goto error;
> > +
> > +	/* Keep PM runtime usage_count incremented on success */
> >  	return 0;
> > +error:
> > +	pm_runtime_put_noidle(&client->dev);  
> 
> This needs to be pm_runtime_put() as the device has been successfully.

Ok.

> 
> > +	return rval;
> >  }
> >  
> >  static int ccs_set_stream(struct v4l2_subdev *subdev, int enable)
> > @@ -3089,12 +3101,9 @@ static int __maybe_unused ccs_suspend(struct device *dev)
> >  	bool streaming = sensor->streaming;
> >  	int rval;
> >  
> > -	rval = pm_runtime_get_sync(dev);
> > -	if (rval < 0) {
> > -		pm_runtime_put_noidle(dev);
> > -
> > +	rval = pm_runtime_resume_and_get(dev);
> > +	if (rval < 0)
> >  		return rval;
> > -	}
> >  
> >  	if (sensor->streaming)
> >  		ccs_stop_streaming(sensor);  
> 

Thanks,
Mauro

---

[PATCH] media: i2c: ccs-core: fix pm_runtime_get_sync() usage count

The pm_runtime_get_sync() internally increments the
dev->power.usage_count without decrementing it, even on errors.

There is a bug at ccs_pm_get_init(): when this function returns
an error, the stream is not started, and RPM usage_count
should not be incremented. However, if the calls to
v4l2_ctrl_handler_setup() return errors, it will be kept
incremented.

At ccs_suspend() the best is to replace it by the new
pm_runtime_resume_and_get(), introduced by:
commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
in order to properly decrement the usage counter automatically,
in the case of errors.

Fixes: 96e3a6b92f23 ("media: smiapp: Avoid maintaining power state information")
Cc: stable@vger.kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c
index b05f409014b2..5ea471fefa3a 100644
--- a/drivers/media/i2c/ccs/ccs-core.c
+++ b/drivers/media/i2c/ccs/ccs-core.c
@@ -1880,21 +1880,33 @@ static int ccs_pm_get_init(struct ccs_sensor *sensor)
 	struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
 	int rval;
 
+	/*
+	 * It can't use pm_runtime_resume_and_get() here, as the driver
+	 * relies at the returned value to detect if the device was already
+	 * active or not.
+	 */
 	rval = pm_runtime_get_sync(&client->dev);
-	if (rval < 0) {
-		pm_runtime_put_noidle(&client->dev);
+	if (rval < 0)
+		goto error;
 
-		return rval;
-	} else if (!rval) {
-		rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->
-					       ctrl_handler);
-		if (rval)
-			return rval;
+	/* Device was already active, so don't set controls */
+	if (rval == 1)
+		return 0;
 
-		return v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
-	}
+	/* Restore V4L2 controls to the suspended device */
+	rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->ctrl_handler);
+	if (rval)
+		goto error;
 
+	rval = v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
+	if (rval)
+		goto error;
+
+	/* Keep PM runtime usage_count incremented on success */
 	return 0;
+error:
+	pm_runtime_put(&client->dev);
+	return rval;
 }
 
 static int ccs_set_stream(struct v4l2_subdev *subdev, int enable)





  reply	other threads:[~2021-05-05 10:57 UTC|newest]

Thread overview: 124+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-05  9:41 [PATCH 00/25] Fix some PM runtime issues at the media subsystem Mauro Carvalho Chehab
2021-05-05  9:41 ` Mauro Carvalho Chehab
2021-05-05  9:41 ` Mauro Carvalho Chehab
2021-05-05  9:41 ` Mauro Carvalho Chehab
2021-05-05  9:41 ` Mauro Carvalho Chehab
2021-05-05  9:41 ` [PATCH 01/25] staging: media: rkvdec: fix pm_runtime_get_sync() usage count Mauro Carvalho Chehab
2021-05-05  9:41   ` Mauro Carvalho Chehab
2021-05-05  9:41   ` Mauro Carvalho Chehab
2021-05-05 12:23   ` Jonathan Cameron
2021-05-05 12:23     ` Jonathan Cameron
2021-05-05  9:41 ` [PATCH 02/25] staging: media: imx7-mipi-csis: " Mauro Carvalho Chehab
2021-05-05  9:41   ` Mauro Carvalho Chehab
2021-05-05  9:41   ` Mauro Carvalho Chehab
2021-05-05 11:06   ` Jonathan Cameron
2021-05-05 11:06     ` Jonathan Cameron
2021-05-05 11:17     ` Mauro Carvalho Chehab
2021-05-05 11:17       ` Mauro Carvalho Chehab
2021-05-05 13:56     ` Rui Miguel Silva
2021-05-05 13:56       ` Rui Miguel Silva
2021-05-05 14:23       ` Mauro Carvalho Chehab
2021-05-05 14:23         ` Mauro Carvalho Chehab
2021-05-05  9:41 ` [PATCH 03/25] media: venus: Rework error fail recover logic Mauro Carvalho Chehab
2021-05-05 11:05   ` Jonathan Cameron
2021-05-05  9:41 ` [PATCH 04/25] media: s5p_cec: decrement usage count if disabled Mauro Carvalho Chehab
2021-05-05 12:24   ` Jonathan Cameron
2021-05-05  9:41 ` [PATCH 05/25] media: i2c: ccs-core: return the right error code at suspend Mauro Carvalho Chehab
2021-05-05 12:24   ` Jonathan Cameron
2021-05-05 12:51   ` Sakari Ailus
2021-05-05  9:41 ` [PATCH 06/25] media: i2c: imx334: fix the pm runtime get logic Mauro Carvalho Chehab
2021-05-05 11:10   ` Jonathan Cameron
2021-05-05 11:24     ` Mauro Carvalho Chehab
2021-05-05 12:26       ` Jonathan Cameron
2021-05-05  9:41 ` [PATCH 07/25] media: exynos-gsc: don't resume at remove time Mauro Carvalho Chehab
2021-05-05  9:41   ` Mauro Carvalho Chehab
2021-05-05 12:27   ` Jonathan Cameron
2021-05-05 12:27     ` Jonathan Cameron
2021-05-05  9:41 ` [PATCH 08/25] media: atmel: properly get pm_runtime Mauro Carvalho Chehab
2021-05-05  9:41   ` Mauro Carvalho Chehab
2021-05-05 12:08   ` Jonathan Cameron
2021-05-05 12:08     ` Jonathan Cameron
2021-06-10  9:04     ` Eugen.Hristev
2021-06-10  9:04       ` Eugen.Hristev
2021-06-10  9:38       ` Mauro Carvalho Chehab
2021-06-10  9:38         ` Mauro Carvalho Chehab
2021-06-10 12:00         ` Eugen.Hristev
2021-06-10 12:00           ` Eugen.Hristev
2021-06-16  8:03           ` Mauro Carvalho Chehab
2021-06-16  8:03             ` Mauro Carvalho Chehab
2021-09-06  8:03           ` Mauro Carvalho Chehab
2021-09-06  8:03             ` Mauro Carvalho Chehab
2021-09-06  8:13             ` Eugen.Hristev
2021-09-06  8:13               ` Eugen.Hristev
2021-09-13 10:26               ` Eugen.Hristev
2021-09-13 10:26                 ` Eugen.Hristev
2021-05-05  9:41 ` [PATCH 09/25] media: hantro: do a PM resume earlier Mauro Carvalho Chehab
2021-05-05  9:41   ` Mauro Carvalho Chehab
2021-05-05  9:41   ` Mauro Carvalho Chehab
2021-05-05 11:34   ` Jonathan Cameron
2021-05-05 11:34     ` Jonathan Cameron
2021-05-05 13:22   ` Ezequiel Garcia
2021-05-05 13:22     ` Ezequiel Garcia
2021-05-05 13:22     ` Ezequiel Garcia
2021-05-05 13:46     ` Mauro Carvalho Chehab
2021-05-05 13:46       ` Mauro Carvalho Chehab
2021-05-05 14:01       ` Ezequiel Garcia
2021-05-05 14:01         ` Ezequiel Garcia
2021-05-05 14:01         ` Ezequiel Garcia
2021-05-05 14:15         ` Mauro Carvalho Chehab
2021-05-05 14:15           ` Mauro Carvalho Chehab
2021-05-05  9:42 ` [PATCH 10/25] media: marvel-ccic: fix some issues when getting pm_runtime Mauro Carvalho Chehab
2021-05-05  9:42 ` [PATCH 11/25] media: mdk-mdp: fix pm_runtime_get_sync() usage count Mauro Carvalho Chehab
2021-05-05  9:42   ` Mauro Carvalho Chehab
2021-05-05  9:42   ` Mauro Carvalho Chehab
2021-05-05  9:42 ` [PATCH 12/25] media: rcar_fdp1: simplify error check logic at fdp_open() Mauro Carvalho Chehab
2021-05-05  9:48   ` Sergei Shtylyov
2021-05-05  9:42 ` [PATCH 13/25] media: rcar_fdp1: fix pm_runtime_get_sync() usage count Mauro Carvalho Chehab
2021-05-05 12:31   ` Jonathan Cameron
2021-05-05  9:42 ` [PATCH 14/25] media: renesas-ceu: Properly check for PM errors Mauro Carvalho Chehab
2021-05-05  9:56   ` Jacopo Mondi
2021-05-05  9:42 ` [PATCH 15/25] media: s5p: fix pm_runtime_get_sync() usage count Mauro Carvalho Chehab
2021-05-05 12:31   ` Jonathan Cameron
2021-05-05  9:42 ` [PATCH 16/25] media: am437x: " Mauro Carvalho Chehab
2021-05-05 12:32   ` Jonathan Cameron
2021-05-08 13:01   ` Lad, Prabhakar
2021-05-05  9:42 ` [PATCH 17/25] media: sh_vou: " Mauro Carvalho Chehab
2021-05-05  9:42 ` [PATCH 18/25] media: mtk-vcodec: fix PM runtime get logic Mauro Carvalho Chehab
2021-05-05  9:42   ` Mauro Carvalho Chehab
2021-05-05  9:42   ` Mauro Carvalho Chehab
2021-05-05 12:32   ` Jonathan Cameron
2021-05-05 12:32     ` Jonathan Cameron
2021-05-05 12:32     ` Jonathan Cameron
2021-05-05  9:42 ` [PATCH 19/25] media: s5p-jpeg: fix pm_runtime_get_sync() usage count Mauro Carvalho Chehab
2021-05-05  9:42   ` Mauro Carvalho Chehab
2021-05-05 12:33   ` Jonathan Cameron
2021-05-05 12:33     ` Jonathan Cameron
2021-05-05  9:42 ` [PATCH 20/25] media: sti/delta: use pm_runtime_resume_and_get() Mauro Carvalho Chehab
2021-05-05 12:01   ` Jonathan Cameron
2021-05-05 12:33     ` Jonathan Cameron
2021-05-05  9:42 ` [PATCH 21/25] media: sunxi: fix pm_runtime_get_sync() usage count Mauro Carvalho Chehab
2021-05-05  9:42   ` Mauro Carvalho Chehab
2021-05-05  9:42   ` Mauro Carvalho Chehab
2021-05-05  9:42 ` [PATCH 22/25] media: sti/bdisp: " Mauro Carvalho Chehab
2021-05-05 12:34   ` Jonathan Cameron
2021-05-05  9:42 ` [PATCH 23/25] media: exynos4-is: " Mauro Carvalho Chehab
2021-05-05  9:42   ` Mauro Carvalho Chehab
2021-05-05 12:20   ` Jonathan Cameron
2021-05-05 12:20     ` Jonathan Cameron
2021-05-05  9:42 ` [PATCH 24/25] media: exynos-gsc: " Mauro Carvalho Chehab
2021-05-05  9:42   ` Mauro Carvalho Chehab
2021-05-05 12:34   ` Jonathan Cameron
2021-05-05 12:34     ` Jonathan Cameron
2021-05-05  9:42 ` [PATCH 25/25] media: i2c: ccs-core: " Mauro Carvalho Chehab
2021-05-05 10:34   ` Sakari Ailus
2021-05-05 10:57     ` Mauro Carvalho Chehab [this message]
2021-05-05 10:58       ` Mauro Carvalho Chehab
2021-05-05 12:35         ` Jonathan Cameron
2021-05-05 14:06           ` Mauro Carvalho Chehab
2021-05-05 16:36             ` Jonathan Cameron
2021-05-05 11:02       ` Sakari Ailus
2021-05-06 15:11 ` [PATCH 00/25] Fix some PM runtime issues at the media subsystem Mauro Carvalho Chehab
2021-05-06 15:11   ` Mauro Carvalho Chehab
2021-05-06 15:11   ` Mauro Carvalho Chehab
2021-05-06 15:11   ` Mauro Carvalho Chehab
2021-05-06 15:11   ` Mauro Carvalho Chehab

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