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Date:   Wed, 26 Feb 2020 17:17:57 +0100
From:   Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= 
        <u.kleine-koenig@pengutronix.de>
To:     Mark Brown <broonie@kernel.org>
Cc:     Jon Hunter <jonathanh@nvidia.com>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
        linux-tegra@vger.kernel.org
Subject: Re: [PATCH] regulator: pwm: Don't warn on probe deferral
Message-ID: <20200226161757.idpzbs3jmayt7ya6@pengutronix.de>
References: <20200224144048.6587-1-jonathanh@nvidia.com>
 <20200224165859.GJ6215@sirena.org.uk>
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On Mon, Feb 24, 2020 at 04:58:59PM +0000, Mark Brown wrote:
> On Mon, Feb 24, 2020 at 02:40:48PM +0000, Jon Hunter wrote:
> > Deferred probe is an expected return value for devm_pwm_get(). Given
> > that the driver deals with it properly, there's no need to output a
> > warning that may potentially confuse users.
> 
> >  		ret = PTR_ERR(drvdata->pwm);
> > -		dev_err(&pdev->dev, "Failed to get PWM: %d\n", ret);
> > +		if (ret != -EPROBE_DEFER)
> > +			dev_err(&pdev->dev, "Failed to get PWM: %d\n", ret);
> 
> This then means that there's no way for users to determine why the
> driver has failed to instantiate which can be frustrating.  It'd be
> better to at least have some dev_dbg() output when deferring so that
> there's something for people to go on without having to instrument the
> code.

Not printing an error message is quite usual however. I think a generic
approach that for example makes the list of devices that should be
retried to probe on the next opportunity inspectable would be nice.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-K?nig            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |