$ sudo Xorg -- -config /etc/X11/xorg.conf-sisusb :1
(The conf file is attached in the email. The session of input device
is missed as I don't want it to use my keyboard in the test)
I could see the X cursor show on the monitor which is connected to
the USB VGA. The X should be running fine, but I lost my current X
in the original monitor. The screen is dark. Unless I press
"Alt+Ctrl+F7" to switch back. Then it will cause the newly started X
be dark. (Should be returned by "Alt+Ctrl+F8")
Seem that they shared the same virtual terminal (is it the right way
to describe the problem?).The "XFree86 Local Multi-User Howto"
suggested a method to solve but require a patched kernel. Any other
way to solve the problem?