[Letux-kernel] [PATCH 2/5] input: twl6040-vibra: add handler to unregister input if module is removed
H. Nikolaus Schaller
hns at goldelico.com
Tue Apr 19 10:05:08 CEST 2016
> Am 19.04.2016 um 09:57 schrieb Dmitry Torokhov <dmitry.torokhov at gmail.com>:
> On Tue, Apr 19, 2016 at 09:33:10AM +0200, H. Nikolaus Schaller wrote:
>>> Am 18.04.2016 um 23:12 schrieb Dmitry Torokhov <dmitry.torokhov at gmail.com>:
>>> On Mon, Apr 18, 2016 at 09:55:38PM +0200, H. Nikolaus Schaller wrote:
>>>> commit 1f9e1470ab34 ("Input: twl6040-vibra - use devm functions")
>>>> converted everything to devm but we still need to call
>>> No, this is not needed, because devm-managed input devices will be
>>> unregistered automatically.
>> Well, it would, if the current driver would use devm for registration. But it appears not to do it that way (line 375):
>> So we either have to fix line 375 or add the proposed explicit unregister call.
>> Research shows me that you did propose devm_input_register_device() some years ago but this API was never included:
> That's because we have what I mentioned in _OR_ portion of that email:
> * devm_input_allocate_device - allocate managed input device
> * @dev: device owning the input device being created
> * Returns prepared struct input_dev or %NULL.
> * Managed input devices do not need to be explicitly unregistered or
> * freed as it will be done automatically when owner device unbinds from
> * its driver (or binding fails). Once managed input device is allocated,
> * it is ready to be set up and registered in the same fashion as regular
> * input device. There are no special devm_input_device_[un]register()
> * variants, regular ones work with both managed and unmanaged devices,
> * should you need them. In most cases however, managed input device need
> * not be explicitly unregistered or freed.
> * NOTE: the owner device is set up as parent of input device and users
> * should not override it.
Hm. If I remember correctly (it is a while ago) we had to add this explicit
unregister mechanism because we got ugly kernel panics otherwise. Indicating
that the input device was still registered and *not* unregistered automatically.
I will test.
BR and thanks,
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