I have upgraded xorg server quite a while ago and it had not resolved the issue at that time.  Just for the completness:

/var/log/dpkg.log.1:2012-07-03 09:53:04 status installed xserver-xorg:amd64 1:7.6+13
/var/log/dpkg.log.1:2012-07-03 09:53:04 status installed xorg:amd64 1:7.6+13
/var/log/dpkg.log.1:2012-07-11 14:56:36 status installed xserver-xorg-core:amd64 2:1.12.1.902-1
/var/log/dpkg.log.1:2012-07-11 16:22:02 status installed xserver-xorg-video-vesa:amd64 1:2.3.1-1+b1
/var/log/dpkg.log.1:2012-07-11 16:22:02 status installed xserver-xorg-video-intel:amd64 2:2.19.0-4
/var/log/dpkg.log.1:2012-07-11 16:22:02 status installed xserver-xorg-video-fbdev:amd64 1:0.4.2-4+b3
/var/log/dpkg.log.1:2012-07-11 16:22:02 status installed xserver-xorg-video-dummy:amd64 1:0.3.5-2+b1
/var/log/dpkg.log.1:2012-07-11 16:22:02 status installed xserver-xorg-video-apm:amd64 1:1.2.3-3
/var/log/dpkg.log.1:2012-07-11 16:22:02 status installed xserver-xorg-input-void:amd64 1:1.4.0-1+b1
/var/log/dpkg.log.1:2012-07-11 16:22:02 status installed xserver-xorg-input-synaptics:amd64 1.6.2-1
/var/log/dpkg.log.1:2012-07-11 16:22:02 status installed xserver-xorg-input-evdev:amd64 1:2.7.0-1+b1
/var/log/dpkg.log.1:2012-07-11 16:22:02 status installed xserver-xorg:amd64 1:7.7+1
/var/log/dpkg.log.1:2012-07-11 16:22:02 status installed xorg:amd64 1:7.7+1
/var/log/dpkg.log.1:2012-07-11 16:22:02 status installed xserver-xorg-dev:amd64 2:1.12.1.902-1
/var/log/dpkg.log.1:2012-07-11 16:22:02 status installed xorg-dev:all 1:7.7+1
/var/log/dpkg.log.1:2012-07-16 11:43:34 status installed xserver-xorg-core-dbg:amd64 2:1.12.1.902-1
/var/log/dpkg.log.1:2012-07-16 11:43:34 status installed xserver-xorg-video-intel-dbg:amd64 2:2.19.0-4
/var/log/dpkg.log.1:2012-07-21 15:35:55 status installed xserver-xorg-core:amd64 2:1.12.3-1
/var/log/dpkg.log.1:2012-07-21 15:35:55 status installed xserver-xorg-core-dbg:amd64 2:1.12.3-1
/var/log/dpkg.log.1:2012-07-21 15:35:55 status installed xserver-xorg-dev:amd64 2:1.12.3-1
/var/log/dpkg.log.1:2012-07-25 09:18:55 status installed xserver-xorg-dev:amd64 2:1.12.3-1
/var/log/dpkg.log.1:2012-07-25 09:18:55 status installed xserver-xorg-core:amd64 2:1.12.3-1
/var/log/dpkg.log.1:2012-07-25 09:18:57 status installed xserver-xorg-core-dbg:amd64 2:1.12.3-1
/var/log/dpkg.log.1:2012-07-25 09:19:58 status installed xserver-xorg-dev:amd64 2:1.12.3-1
/var/log/dpkg.log.1:2012-07-25 09:19:58 status installed xserver-xorg-core:amd64 2:1.12.3-1
/var/log/dpkg.log.1:2012-07-25 09:20:00 status installed xserver-xorg-core-dbg:amd64 2:1.12.3-1
/var/log/dpkg.log.1:2012-07-26 20:15:33 status installed xserver-xorg-core-dbg:amd64 2:1.12.3-1
/var/log/dpkg.log:2012-08-08 23:12:08 status installed xserver-xorg-input-synaptics:amd64 1.6.2-1
/var/log/dpkg.log:2012-08-09 11:00:56 status installed xserver-xorg-input-synaptics-dev:all 1.5.99.902-1
/var/log/dpkg.log:2012-08-09 11:00:56 status installed xserver-xorg-input-synaptics:amd64 1.5.99.902-1
/var/log/dpkg.log:2012-08-15 12:45:23 status installed xserver-xorg-input-synaptics-dev:all 1.6.2+git44-ge28575b-1~yarik0
/var/log/dpkg.log:2012-08-15 12:45:23 status installed xserver-xorg-input-synaptics:amd64 1.6.2+git44-ge28575b-1~yarik0


as you see I have built and installed current master of the synaptics but had no chance yet to restart X to see if crash comes back... I will report back whenever that happens