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Message-ID: <f07b3156-2bc8-49bf-bc08-e40209b89cf1@gmx.de>
Date: Mon, 22 Jan 2024 16:03:29 +0100
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Subject: Re: [PATCH v2] platform/x86: wmi: Use ACPI device name in netlink
 event
To: =?UTF-8?Q?Ilpo_J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>,
 Hans de Goede <hdegoede@redhat.com>
Cc: Andy Shevchenko <andy@kernel.org>, platform-driver-x86@vger.kernel.org,
 LKML <linux-kernel@vger.kernel.org>
References: <20240121200824.2778-1-W_Armin@gmx.de>
 <1862d74a-7b15-48e3-896b-30dda835f28f@redhat.com>
 <61d23b7d-8e47-acf8-f3b7-bea1544ca8fa@linux.intel.com>
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From: Armin Wolf <W_Armin@gmx.de>
In-Reply-To: <61d23b7d-8e47-acf8-f3b7-bea1544ca8fa@linux.intel.com>
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Am 22.01.24 um 13:47 schrieb Ilpo J=C3=A4rvinen:

> On Mon, 22 Jan 2024, Hans de Goede wrote:
>> On 1/21/24 21:08, Armin Wolf wrote:
>>> The device name inside the ACPI netlink event is limited to
>>> 15 characters, so the WMI device name will get truncated.
>>>
>>> This can be observed with kacpimon when receiving an event
>>> from WMI device "9DBB5994-A997-11DA-B012-B622A1EF5492":
>>>
>>> 	netlink:  9DBB5994-A997- 000000d0 00000000
>>>
>>> Fix this by using the shorter device name from the ACPI
>>> bus device instead. This still allows users to uniquely
>>> identify the WMI device by using the notify id (0xd0).
>>>
>>> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
>>> ---
>>> Changes since v1:
>>> - use acpi_dev_name() helper function
>> I'm a bit divided on this patch. I agree the new way of doing
>> things is better, but technically this is a bit of a userspace API
>> break.
>>
>> I guess we could hope that nothing depends on the old netlink API
>> format / name but I'm not sure we can rely on that ...
>>
>> Ilpo, Andy do you have any opinion on this ?
> Hi Armin,
>
> Have you tried to conduct debian code search to find the code using this=
?
>
I did, but i found nothing.

I am also preparing to properly initialize the device_class field in anoth=
er patch,
and this also has the potential of breaking userspace if some users create=
d custom
acpid configs to listen to those events.

I think we can revert those changes anytime if someones turns out to be ac=
tually depending
on them.

Armin Wolf