linux-kernel - Re: [PATCH] gpiolib: suppress error message on EPROBE

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Message-ID: <7efffc52-1332-5d98-e6b8-634d5ee9082e@lechnology.com>
Date:   Sat, 17 Feb 2018 21:47:49 -0600
From:   David Lechner <david@...hnology.com>
To:     Linus Walleij <linus.walleij@...aro.org>
Cc:     linux-gpio@...r.kernel.org,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] gpiolib: suppress error message on EPROBE_DEFER

On 02/07/2018 06:57 AM, Linus Walleij wrote:
> On Sun, Jan 21, 2018 at 9:32 PM, David Lechner <david@...hnology.com> wrote:
> 
>> This suppresses printing an error message during probe of gpio drivers
>> when the error is EPROBE_DEFER.
>>
>> Cc: Linus Walleij <linus.walleij@...aro.org>
>> Signed-off-by: David Lechner <david@...hnology.com>
> 
> I'm not sure about this.
> 
> GPIO can be very basic system components. If we don't
> print this, defer a few times (for some reason) and then
> the kernel gives up on retrying, silently (as it happens)
> there is no trace in dmesg of what happened. That makes
> things hard to debug.
> 
> This happened to me with some other driver, so it is not
> a made up example.
> 
> What about an explicit deferral message for now?

so you mean something like this?

if (err == -EPROBE_DEFER)
	dev_info(dev, "deferring probe\n")
else
	dev_err(dev, "... failed to register\n")