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Date:   Sun, 23 Dec 2018 18:17:04 +0100
From:   Christian Brauner <christian@brauner.io>
To:     Marcus Meissner <christian.brauner@canonical.com>
Cc:     linux-kernel@vger.kernel.org, dmitry.torokhov@gmail.com,
        gregkh@linuxfoundation.org
Subject: Re: FYI: Userland breakage caused by udev bind commit
Message-ID: <20181223171703.s7jm6fkyosnsf33z@brauner.io>
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On Sun, Dec 23, 2018 at 05:49:54PM +0100, Marcus Meissner wrote:
> Hi,
> 
> I am the maintainer of libmtp and libgphoto2
> 
> Some months ago I was made aware of this bug:
> 	https://bugs.kde.org/show_bug.cgi?id=387454
> 
> This was fallout identified to come from this kernel commit:
> 
> 	commit 1455cf8dbfd06aa7651dcfccbadb7a093944ca65
> 	Author: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> 	Date:   Wed Jul 19 17:24:30 2017 -0700

Fwiw, the addition of {un}bind events has caused issues for
systemd-udevd as well and is tracked here:
https://github.com/systemd/systemd/issues/7587
I haven't been aware of this until yesterday and it seems that so far
this hasn't been brought up on lkml until you did now.

> 
> If distributions would be using libmtp and libgphoto2 udev rules
> that just triggered on "add" events, and not the new "bind" events,
> the missing "attribute tagging" of the "bind" events would confused the
> KDE Solid device detection and make the devices no longer detected.
> 
> This did not affect distributions that rely on the newer "hwdb"
> device detection method.
> 
> I have released fixed libmtp and libgphoto2 versions in November, so
> this is under control, but wanted to bring this up as a "kernel caused
> userland breakage".
> 
> Ciao, Marcus