Created attachment 118399 [details]
weston-launcher's log

Display: Dell U2311H, 1920x1080@60.
Distro: Arch Linux i686
Linux 4.1.6-ck
Wayland 1.9.0
Weston 1.9.0
xorg-server 1.17.2-4
xorg-server-xwayland 1.17.2-4
libinput 1.0.1
xf86-input-libinput 0.14.0-3
Simple USB mouse A4Tech X7 F5
Mesa 11 (git, a1ac742)
 
I rotated my display vertically, so now my resolution is 1080x1920. (I use my display vertically almost always because it is very comfortable to read/write text/code when I can see a lot and scroll rarely).

When I open any X11 app (in Weston):
1. I can move successfully mouse pointer along the axis X (all of the 1080 pixels).
2. I can move successfully mouse pointer along the axis Y within only the top 1080 pixels (relative to the screen, not the window).
3. If I move mouse pointer below the top 1080px, the app (!) still thinks that Y=1080, though I (!) see that mouse pointer's Y is actually > 1080.
4. If I move the window to the bottom of the screen, then I can't click/scroll anything (Y relative to screen is > 1080) in it. I can't even move the window by clicking its title bar using the left mouse button. Though I can move the window by using Weston's Super+LMB.
Both xf86-video-ati and modesetting produce the same result.

I *think* there is something in the XWayland's code like:
max_cursor_y = maxResolutionHeight;
return min(cursor_y, max_cursor_y);
which should be changed to
max_cursor_y = (rotate_degree == 90 || rotate_degree == 270)
               ? max_resolution_width : max_resolution_height;
return min(cursor_y, max_cursor_y);

There is no such bug with mouse in X11 (I use it with libinput too).