linux-kernel - Re: [PATCH 4.19 070/276] media: stm32-dcmi: return appropriate error codes during probe

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Message-ID: <20190531093132.GB23111@amd>
Date:   Fri, 31 May 2019 11:31:32 +0200
From:   Pavel Machek <pavel@...x.de>
To:     Fabien DESSENNE <fabien.dessenne@...com>
Cc:     Pavel Machek <pavel@...x.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>,
        Hugues FRUCHET <hugues.fruchet@...com>,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        Mauro Carvalho Chehab <mchehab+samsung@...nel.org>,
        Sasha Levin <sashal@...nel.org>
Subject: Re: [PATCH 4.19 070/276] media: stm32-dcmi: return appropriate error
 codes during probe

On Fri 2019-05-31 08:39:18, Fabien DESSENNE wrote:
> Hi Pavel
> 
> 
> On 31/05/2019 10:19 AM, Pavel Machek wrote:
> > Hi!
> >
> >> [ Upstream commit b5b5a27bee5884860798ffd0f08e611a3942064b ]
> >>
> >> During probe, return the provided errors value instead of -ENODEV.
> >> This allows the driver to be deferred probed if needed.
> > This is not correct AFAICT.
> 
> 
> The driver gets defer probed *if needed*. *if needed* is for the case 
> where platform_get_irq returns -EPROBE_DEFER, which happens if the irq 
> controller is not ready yet.
> 
> Of course, for the other cases, the probe would just fail.

"This" was referring to code below. Sorry for confusion.

Best regards,
								Pavel

> >> +++ b/drivers/media/platform/stm32/stm32-dcmi.c
> >> @@ -1673,8 +1673,9 @@ static int dcmi_probe(struct platform_device *pdev)
> >>   
> >>   	irq = platform_get_irq(pdev, 0);
> >>   	if (irq <= 0) {
> >> -		dev_err(&pdev->dev, "Could not get irq\n");
> >> -		return -ENODEV;
> >> +		if (irq != -EPROBE_DEFER)
> >> +			dev_err(&pdev->dev, "Could not get irq\n");
> >> +		return irq;
> >>   	}
> >>   
> >>   	dcmi->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > irq == 0 is clearly means error here, but will be interpretted as
> > success when returned to the caller.
> 
> 
> Thank you for pointing this.
> 
> It shall be 'return irq ? irq : -ENXIO;'  I will send a fix for this.
> 
> 
> >
> > As device is not initialized at that point, I'd expect some kind of
> > crash later.
> > 									Pavel

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DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

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