Bug#531305: Mouse acceleration not consistent under Xephyr and native X

[Daniel Pocock <daniel@pocock.com.au>]

Package: xserver-xephyr


I'm using the script given below to start Xephyr from gdm, with the 
intention of creating a `multi-seat' environment.

I can start my X session in one of two ways:
a) native X (gdm logs in to :0)
b) Xephyr (gdm logs in to :1, which is really Xephyr on :0.0)

In either case, I have the same home directory, same Gnome settings, same X binaries, etc.

In case (b), I notice mouse acceleration is not consistent with case (a).  It is a little slower/more cumbersome.  When I switch between (a) and (b), I feel like I am working on a different machine, due to this change in mouse behaviour.

This is my Xephyr command line:

# ps ax | grep Xephyr
1983 ?        S     14:55 /usr/bin/Xephyr :1 -audit 0 -screen 1920x1200 
-dpi 96 +kb r -auth /var/lib/gdm/:1.Xauth

The gdm settings:

[server-screen0]
name=screen0
command=/usr/local/bin/launch-xephyr -display :0.0 -xauthority 
/var/lib/gdm/:0.Xauth -audit 0 -screen 1920x1200 -dpi 96 +kb r
handled=true
flexible=false




$ cat /usr/local/bin/launch-xephyr
#!/bin/bash

trap "" usr1

XEPHYR=/usr/bin/Xephyr

args=()

while [ ! -z "$1" ]; do
if [[ "$1" == "-xauthority" ]]; then
 shift
 if [ ! -z "$1" ]; then
   export XAUTHORITY="$1"
 fi
elif [[ "$1" == "-display" ]]; then
 shift
 if [ ! -z "$1" ]; then
   export DISPLAY="$1"
 fi
else
 if ! expr match $1 'vt[0-9][0-9]*' >/dev/null; then
   args=("${args[@]}" "$1")
 fi
fi

shift
done

/usr/bin/xset s noblank
/usr/bin/xset s off
/usr/bin/xset -dpms

exec $XEPHYR "${args[@]}"