linux-kernel - Re: [PATCH] regulator: pwm: Don't warn on probe deferral

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Date:   Fri, 6 Mar 2020 08:51:29 +0100
From:   Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>
To:     Mark Brown <broonie@...nel.org>
Cc:     Jon Hunter <jonathanh@...dia.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Thierry Reding <thierry.reding@...il.com>,
        linux-kernel@...r.kernel.org, linux-pwm@...r.kernel.org,
        linux-tegra@...r.kernel.org
Subject: Re: [PATCH] regulator: pwm: Don't warn on probe deferral

On Wed, Feb 26, 2020 at 04:39:05PM +0000, Mark Brown wrote:
> On Wed, Feb 26, 2020 at 05:17:57PM +0100, Uwe Kleine-König wrote:
> > On Mon, Feb 24, 2020 at 04:58:59PM +0000, Mark Brown wrote:
> 
> > > 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
> 
> Usual yet also frustraing.
> 
> > approach that for example makes the list of devices that should be
> > retried to probe on the next opportunity inspectable would be nice.
> 
> That's not really the issue, the bigger issue is trying to figure out
> why things are stuck - what exactly caused things to fail to
> instantiate.

I wonder if we should do something like:

	ret = some_call(some, args);
	if (ret) {
		if (emit_errmsg_for_err(ret))
			dev_err(dev, "some_call failed: %pE\n", ERR_PTR(ret));
		return ret;
	}

and have emit_errmsg_for_err return true if ret != -EPROBE_DEFER or some
kernel parameter is given.

Best regards
Uwe

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