linux-kernel - Re: [PATCH] driver core: Make Kconfig text for DEBUG_TEST_DRIVER

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Message-ID: <CAMuHMdVZFTeRDpRkF4s-=XM+BAT0=W4Lm=o8C4eYBTR4uUSBQw@mail.gmail.com>
Date:   Mon, 31 Oct 2016 13:28:49 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Laura Abbott <labbott@...hat.com>, Rob Herring <robh@...nel.org>,
        Arnd Bergmann <arnd@...db.de>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        linux-clk <linux-clk@...r.kernel.org>
Subject: Re: [PATCH] driver core: Make Kconfig text for DEBUG_TEST_DRIVER_REMOVE
 stronger

Hi Greg,

On Mon, Oct 31, 2016 at 1:21 PM, Greg Kroah-Hartman
<gregkh@...uxfoundation.org> wrote:
> On Mon, Oct 31, 2016 at 11:12:45AM +0100, Geert Uytterhoeven wrote:
>> On Fri, Oct 7, 2016 at 6:09 PM, Laura Abbott <labbott@...hat.com> wrote:
>> > The current state of driver removal is not great.
>> > CONFIG_DEBUG_TEST_DRIVER_REMOVE finds lots of errors. The help text
>> > currently undersells exactly how many errors this option will find. Add
>> > a bit more description to indicate this option shouldn't be turned on
>> > unless you actually want to debug driver removal. The text can be
>> > changed later when more drivers are fixed up.
>>
>> Indeed, this is failing miserably for e.g. SoC clock drivers using
>> platform_driver_probe(), which are never retried, rendering the complete
>> system useless.
>
> Why are they never retried?

Because platform_driver_probe() is meant for non-hotpluggable devices,
and unregisters the platform driver immediately if probe fails.
See also the comments for __platform_driver_probe():

 * Note that this is incompatible with deferred probing.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds