Re: [PATCH] driver core: Make Kconfig text for DEBUG_TEST_DRIVER_REMOVE stronger

From: Rob Herring
Date: Mon Oct 31 2016 - 10:11:27 EST


On Mon, Oct 31, 2016 at 7:28 AM, Geert Uytterhoeven
<geert@xxxxxxxxxxxxxx> wrote:
> Hi Greg,
>
> On Mon, Oct 31, 2016 at 1:21 PM, Greg Kroah-Hartman
> <gregkh@xxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxx> 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():

My patch "driver core: skip removal test for non-removable drivers"
fixes this case. It seems to have dropped from Greg's queue, so I'll
resend.

Rob