On Mon, Dec 24, 2018 at 10:12:29AM +0100, Greg KH wrote: > 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.torok...@gmail.com> > > Date: Wed Jul 19 17:24:30 2017 -0700 > > > > 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". > > This is complex, sorry. When this first commit was merged, we did get > some reports of problems, so we reverted it. Dmitry worked through the > issues and then we added it back again. > > That was back in July of 2017, and since then, we had not heard of any > problems that happened until this month, a very long time. > > So I really don't understand the root problem here, all of the distros > that have been shipping kernels with this code for over a year didn't > seem to have any issues. My systems never had any issues, and so I > can't figure out what suddenly changed to cause problems. > > Was it the fact that we all are using distros that use hwdb? Who does > _not_ use hwdb these days? Heck, I would have expected Debian to report > problems as they are the ones that are known to use old userspace code > with kernel developers using new kernels. > > So what changed to cause the problem recently?
I think this is new systemd that had my patch to handle bind/unbind instead of ignoring them is catching up in distros. So: - old systemd with old kernels OK - old systemd with new kernels OK - new systemd with old kernels OK - new systemd with new kernels - NOT OK - losing tags on bind Systemd folks merged my patch to disable bind/unbind again until we teach it to no longer flush entire device state on each new uevent and it should be well now. Thanks. -- Dmitry
