Mouse problems with mixed monitor rotations

[Adr3nal D0S]

I just submitted bug 13624 for this problem,
https://bugs.freedesktop.org/show_bug.cgi?id=13624.

Now that basic xrandr works with my configuration, I have found problems with
the mouse cursor.  I have a monitor configuration where my laptop's LVDS is
oriented normally but my external VGA-0 monitor is left-rotated into portrait
orientation as follows:

    +-----+ +---+
    |     | |   |
    +-----+ |   |
            |   |
            +---+

Here is the pertinent output from xrandr:
    $ xrandr -q
    Screen 0: minimum 320 x 200, current 3120 x 1600, maximum 3520 x 1920
    VGA-0 connected 1200x1600+1920+0 left (normal left inverted right) 408mm x
306mm
       1600x1200      60.0*+   59.9
    ...
    LVDS connected 1920x1200+0+0 (normal left inverted right) 0mm x 0mm
       1920x1200      60.0*+
    ...

There are two related issues.  The mouse cursor is left-rotated and appears
correctly on the portrait monitor.  But it is turned on its side when moved to
the landscape laptop display.  This is not _too_ disturbing, but could be
better.

It gets even stranger, if you set the position of the VGA-0 to overlap the
region displayed by the LVDS and move the mouse into the shared area, it will
be oriented correctly on the VGA-0 and incorrectly on the LVDS.  Now I under
stand from a video-memory perspective they are both being drawn in the same
"direction".

The second more important bug is that on the landscape display the cursor's
apparent and actual hot point differ.  Visually the mouse points to what seems
to be the lower-left corner of its sprite space, but the actual hot point as
detected by hovering over a button or clicking on something is the upper-left
corner.  This is further evidenced by the fact that you cannot move the pointer
clear to the top of the screen.