linux-kernel - Re: [PATCH] media: pxa_camera: disable and unprepare the clock source on error

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Date:   Mon, 11 Dec 2017 23:43:15 +0200
From:   Laurent Pinchart <laurent.pinchart@...asonboard.com>
To:     Flavio Ceolin <flavio.ceolin@...el.com>
Cc:     linux-kernel@...r.kernel.org,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Hans Verkuil <hans.verkuil@...co.com>,
        Petr Cvek <petr.cvek@....cz>,
        Sakari Ailus <sakari.ailus@....fi>,
        Niklas Söderlund 
        <niklas.soderlund+renesas@...natech.se>,
        Julia Lawall <Julia.Lawall@...6.fr>,
        Arnd Bergmann <arnd@...db.de>,
        "open list:MEDIA INPUT INFRASTRUCTURE (V4L/DVB)" 
        <linux-media@...r.kernel.org>
Subject: Re: [PATCH] media: pxa_camera: disable and unprepare the clock source on error

Hi Flavio,

On Monday, 11 December 2017 23:05:46 EET Flavio Ceolin wrote:
> > On Wednesday, 6 December 2017 18:38:50 EET Flavio Ceolin wrote:
> >> pxa_camera_probe() was not calling pxa_camera_deactivate(),
> >> responsible to call clk_disable_unprepare(), on the failure path. This
> >> was leading to unbalancing source clock.
> >> 
> >> Found by Linux Driver Verification project (linuxtesting.org).
> > 
> > Any chance I could sign you up for more work on this driver ? :-)
> 
> Definetely, this would be great :)

Actually it looks like the work I thought was needed has already been 
performed. The pxa-camera driver used to make use of the soc-camera framework, 
which we are trying to remove, and occurrences of soc_camera in the code gave 
me the wrong idea that the driver was still based on that framework. It seems 
this isn't the case. Thank you for making me happy :-)

> >> Signed-off-by: Flavio Ceolin <flavio.ceolin@...el.com>
> > 
> > Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
> > 
> > I expect Hans Verkuil to pick up the patch.
> > 
> >> ---
> >> 
> >>  drivers/media/platform/pxa_camera.c | 4 +++-
> >>  1 file changed, 3 insertions(+), 1 deletion(-)
> >> 
> >> diff --git a/drivers/media/platform/pxa_camera.c
> >> b/drivers/media/platform/pxa_camera.c index 9d3f0cb..7877037 100644
> >> --- a/drivers/media/platform/pxa_camera.c
> >> +++ b/drivers/media/platform/pxa_camera.c
> >> @@ -2489,7 +2489,7 @@ static int pxa_camera_probe(struct platform_device
> >> *pdev)
> >> 	dev_set_drvdata(&pdev->dev, pcdev);
> >>  	err = v4l2_device_register(&pdev->dev, &pcdev->v4l2_dev);
> >>  	if (err)
> >> -		goto exit_free_dma;
> >> +		goto exit_deactivate;
> >> 
> >>  	pcdev->asds[0] = &pcdev->asd;
> >>  	pcdev->notifier.subdevs = pcdev->asds;
> >> @@ -2525,6 +2525,8 @@ static int pxa_camera_probe(struct platform_device
> >> *pdev)
> >> 	v4l2_clk_unregister(pcdev->mclk_clk);
> >>  exit_free_v4l2dev:
> >>  	v4l2_device_unregister(&pcdev->v4l2_dev);
> >> +exit_deactivate:
> >> +	pxa_camera_deactivate(pcdev);
> >>  exit_free_dma:
> >>  	dma_release_channel(pcdev->dma_chans[2]);
> >>  exit_free_dma_u:

-- 
Regards,

Laurent Pinchart