[ubuntu-x] Update to xserver-xorg-input-synaptics to fix evdev probing issues

Chase Douglas chase.douglas at canonical.com
Wed Sep 1 21:18:38 BST 2010

Hi Chris, Bryce,

The current synaptics code has issues when run on Linux and configuring
trackpad devices for input modules other than synaptics. The following
is a description of events that can cause bug 624985

Two touchpad devices A and B
X enumerates A before B
They both have a /dev/input/event* node and a /dev/input/mouse* node
I set up xorg.conf to use evdev for A
A gets handled by evdev
B's /dev/input/mouse* node gets probed by synaptics
it doesn't match /dev/input/event* in the synaptics probe function, so
synaptics runs the eventcomm AutoDevProbe callback
the AutoDevProbe callback finds the first evdev node that isn't grabbed
by synaptics already
in this case, it finds A and grabs it

The fix, as noted by Peter Hutterer on #xorg-devel, is to not let
synaptics process device nodes other than evdev. A more proper fix may
be modifying the synaptics driver, but this would be much more
intrusive. I will try to follow up on that later.

I've pushed a new version of the synaptics package to:

git://git.debian.org/users/corp186-guest/xserver-xorg-input-synaptics.git ubuntu-evdev

Please review the changes and upload the new package after beta freeze
if all looks well. If you are interested in testing it out, I've pushed
a test package to ppa:utouch-team/utouch.


-- Chase

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