linux-kernel - Re: [PATCH] leds: simatic-ipc-leds-gpio: do not run into endless EPROBE

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Date:   Fri, 3 Feb 2023 07:59:46 +0000
From:   Lee Jones <lee@...nel.org>
To:     Henning Schild <henning.schild@...mens.com>
Cc:     Pavel Machek <pavel@....cz>, Hans de Goede <hdegoede@...hat.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        linux-leds@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] leds: simatic-ipc-leds-gpio: do not run into endless
 EPROBE_DEFER loop

On Thu, 02 Feb 2023, Henning Schild wrote:

> Am Wed, 25 Jan 2023 19:17:11 +0100
> schrieb Henning Schild <henning.schild@...mens.com>:
> 
> > Should the driver providing our GPIOs not be available we used to
> > return -EPORBE_DEFER out of the probe function and cause a
> > potentially endless loop that also printed a lot to the kernel log.
> > 
> > ...
> > leds-gpio leds-gpio: cannot find GPIO chip igpio-f7188x-2, deferring
> > leds-gpio leds-gpio: Skipping unavailable LED gpio 0 (red:status-1)
> > ...
> > 
> > The "leds-gpio" just ignores all entries and would never try again
> > even if the GPIOs show up later. But our extra two GPIOs could cause
> > that loop, in which we would even register/unregister "leds-gpio" and
> > cause all the printing.
> > 
> > If any of those two extra GPIOs is not there, return with -ENODEV
> > instead of -EPROBE_DEFER.
> 
> This is a really bad idea. The real fix for the future will be to
> write individual drivers which clearly describe their dep chains.
> 
> This patch should not be merged.

Dropped.

-- 
Lee Jones [李琼斯]