From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-bluetooth@vger.kernel.org,
"Dmitry Torokhov" <dmitry.torokhov@gmail.com>,
"Marcel Holtmann" <marcel@holtmann.org>,
"Kay Sievers" <kay.sievers@vrfy.org>,
"Zbigniew Jędrzejewski-Szmek" <zbyszek@in.waw.pl>,
systemd-devel@lists.freedesktop.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 BlueZ] hid2hci: Fix udev rules for linux-4.14+
Date: Wed, 5 Dec 2018 21:40:51 +0200 [thread overview]
Message-ID: <20181205194051.GU9144@intel.com> (raw)
In-Reply-To: <20181205192036.GB434@kroah.com>
On Wed, Dec 05, 2018 at 08:20:36PM +0100, Greg Kroah-Hartman wrote:
> On Wed, Dec 05, 2018 at 05:40:32PM +0200, Ville Syrjälä wrote:
> > On Wed, Dec 05, 2018 at 08:06:21AM +0100, Greg Kroah-Hartman wrote:
> > > On Tue, Dec 04, 2018 at 10:41:17PM +0200, Ville Syrjala wrote:
> > > > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > >
> > > > Since commit 1455cf8dbfd0 ("driver core: emit uevents when
> > > > device is bound to a driver") the kernel started emitting
> > > > "bind" and "unbind" uevents which confuse the hid2hci
> > > > udev rules.
> > > >
> > > > The symptoms on an affected machine (Dell E5400 in my case)
> > > > include bluetooth devices not appearing and udev hogging
> > > > the cpu as it's busy processing a constant stream of these
> > > > "bind"+"unbind" uevents.
> > >
> > > What is causing a "stream" of bind and unbind events? This only happens
> > > when a device is attached to a driver or removed from a driver, which is
> > > caused by something else happening.
> >
> > Not sure if it's just due to this thing causing devices to
> > appear/disappear during bind/unbind events or what.
>
> Someone has to be telling the kernel to bind/unbind from a driver to
> a device, it doesn't do it on its own. Look at your other rules/scripts
> for that.
>
> Also note that the kernel has been doing this for over a year now (since
> 4.l4), what just happened in 4.19 to cause this to be an issue?
It became an issue for me after I got a machine that suffers from
this. The regression has been present ever since commit 1455cf8dbfd0
("driver core: emit uevents when device is bound to a driver").
You need a Dell E5400 or something similar to see it since those
have these magic bluetooth devices or whatever.
>
> > > This should not be a normal
> > > occurance, unless something odd is happening to your hardware?
> >
> > It's not specific to my hardware. Lot's of people are affected.
> > See eg.
> > https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1759836
> >
> > Acutally looking through that bug it seems someone else noticed
> > hid2hci failing lot in the logs. So maybe it's just that we already
> > switched the mode during "add", and then we try to redo the same
> > thing during "bind" which fails, and that then causes and unbind?
>
> You have to manually unbind the device, the kernel does not do that. So
> perhaps you have a broken udev rule somewhere else that would do
> something odd like unbind/bind?
>
> I don't see this happening on my systems, but hey, I know better than to
> run Ubuntu :)
As do I. And you don't see it because you don't have the right
hardware.
--
Ville Syrjälä
Intel
next prev parent reply other threads:[~2018-12-05 19:41 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-07 13:06 [PATCH bluez] hid2hci: Fix udev rules for linux-4.14+ Ville Syrjala
2018-05-07 17:44 ` [systemd-devel] " Zbigniew Jędrzejewski-Szmek
2018-06-20 16:46 ` Ville Syrjälä
2018-06-20 16:42 ` [PATCH v2] " Ville Syrjala
2018-11-05 17:54 ` Ville Syrjälä
2018-12-04 20:41 ` [PATCH v2 BlueZ] " Ville Syrjala
2018-12-05 7:06 ` Greg Kroah-Hartman
2018-12-05 15:40 ` Ville Syrjälä
2018-12-05 19:09 ` Dag B
2018-12-05 19:21 ` Greg Kroah-Hartman
2018-12-05 19:20 ` Greg Kroah-Hartman
2018-12-05 19:40 ` Ville Syrjälä [this message]
2018-12-05 19:49 ` Greg Kroah-Hartman
2019-04-23 15:41 ` Ville Syrjälä
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