Date: Mon, 23 Sep 2013 17:20:18 +0200
From: Johan Hovold <jhovold@gmail.com>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Johan Hovold <jhovold@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Grant Likely <grant.likely@linaro.org>,
        Mark Brown <broonie@linaro.org>, linux-kernel@vger.kernel.org,
        linux-mmc@vger.kernel.org, linux-mtd@lists.infradead.org,
        linux-pcmcia@lists.infradead.org, linux-usb@vger.kernel.org,
        linux-fbdev@vger.kernel.org
Subject: Re: [PATCH 0/7] driver core: prevent deferred probe with
 platform_driver_probe
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 <20130923145029.GV30088@pengutronix.de>
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On Mon, Sep 23, 2013 at 04:50:29PM +0200, Sascha Hauer wrote:
> On Mon, Sep 23, 2013 at 04:27:25PM +0200, Johan Hovold wrote:
> > Deferred probing cannot be used with platform_driver_probe as by the
> > time probing is retried either the driver has been unregistered or its
> > probe function has been set to platform_drv_probe_fail.
> > 
> > With commit e9354576 ("gpiolib: Defer failed gpio requests by default")
> > the gpio subsystem started returning -EPROBE_DEFER, which in turn
> > several platform drivers using platform_driver_probe return to driver
> > core. Other subsystems (e.g. regulator) has since started doing the
> > same.
> > 
> > The first patch in this series prevents platform drivers using
> > platform_driver_probe from requesting probe deferral while warning that
> > it is not supported.
> > 
> > The remaining patches move six platform-driver probe functions that rely
> > on gpio_request out of __init. There are likely other probe functions
> > that might return -EPROBE_DEFER and should be moved out of __init as
> > well.
> 
> As usually when I read this I wonder why platform_driver_probe exists
> anyway. The only advantage I can think off is that the probe functions
> are in __init and thus can be disposed of later. Now you remove the
> __init annotations from these probe functions. Wouldn't it be better to
> convert the drivers to regular platform_driver_register instead?

Perhaps that paragraph was a bit unclear: I move them out of __init
_and_ use platform_driver_register instead of platform_driver_probe as
well.

Johan
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