Re: [libgpiod v1.6.x][PATCH] tests: mockup: unbind mockup devices before unloading the module

[Kent Gibson <warthog618@gmail.com>]

On Mon, Aug 21, 2023 at 05:33:39PM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> 
> gpio-mockup relies on the GPIO devices being registered in module's __init
> function and them being unregistered in __exit. This works with the GPIO
> subsystem as it only takes a reference to the underlying owner module when
> a GPIO descriptor is requested and not when the GPIO device is
> instantiated.
> 
> This behavior may change in the future in the kernel so make the behavior
> of libgpiomockup more correct and have it unbind all mockup devices over
> sysfs before unloading the module.
> 

Never knew that unbinding was even an option.
Maybe update gpio-mockup's documentation?

Just clarifying what the potential impact of the existing libgpiomockup
behaviour and future kernel behaviour is - the kernel may log errors but
otherwise correctly handle userspace unloading behaving badly?
So this patch is pre-emptory noise reduction?

Cheers,
Kent.