where mouse is drawn on guest does not match mouse coordinates -> fixed in SVN

Could you please attach your guest xorg.conf file? I am wondering whether you have fixed the virtual Y resolution to 1024 or something similar. Of course, this should not cause the problem you are seeing, but knowing might help us fix it.

I'm trying to use resolutions where Y is 950. So the VB window fits nicely in my screen without the use of scroll bars. My host resolution is 1050 pixels high.

The relevant parts of xorg.conf would be:

Section "Device"

Identifier "Generic Video Card"

Driver "vboxvideo"

BusID "PCI:0:2:0"

EndSection?

Section "Screen"

Identifier "Default Screen" Device "Generic Video Card" Monitor "Generic Monitor" DefaultDepth? 24 SubSection? "Display"

Depth 24 Modes "1400x940" "1200x940" "1280x854" "1024x768" "800x600" "640x480"

EndSubSection?

EndSection?

All of this wouldn't matter if the dynamic desktop resizing function worked like it does when the guest is Windows and Ubuntu. But for some reason it doesn't work with Debian.

Reproduced it on a 32bit Etch guest, but only when I add "1280x1024" to the list of resolutions that you gave. Dynamic resizing doesn't work on Etch because it relies on features added in Xorg server 1.3 (RandR 1.2).

Update: This is still happening for me with VirtualBox 2.0.4.

Bump. Any news on this?

Problem still exists in VirtualBox 2.0.6.

The mouse is always out of alignment when using low resolution SDL fullscreen modes in the guest, such as running "tuxpaint --fullscreen".

I should mention I am on the latest (2.0.6) with an Ubuntu 8.10 guest on an Ubuntu 8.04 host.

Problem still exists in VirtualBox 2.1 released today.

My xorg.conf file contains:

SubSection? "Display"

Depth 24 Modes "1650x940" "1280x1024" "1024x768" "800x600" "640x480"

EndSubSection?

I run at 1650x940 simply because it fills up the right amount of my host's screen that I can still access the top bar. But due to this mouse issue, I must run with mouse integration disabled.

Does it change anything if you change the resolution to something where the width is divisible by 8?

I modified my /etc/X11/xorg.conf file (relevant portion posted in my comment above) to try the following resolutions:

1650x940 (neither width nor height are multiples of 8) 1648x940 (width is multiple of 8) 1650x936 (height is multiple of 8) 1648x936 (both width and height are multiple of 8)

Same incorect behaviour with all 4 of these resoltuions. The mouse is in sync at the top of the screen, but as you move down, the mouse is less and less in sync. The mouse is drawn higher up than where the "hidden true" mouse is located.

I have investigated this a bit more, and I have discovered the reason for the wrong mouse position, but have no idea how to fix it. The reason is that when we report the absolute position of the pointer to the X server, the server interprets this as an absolute position on the virtual desktop. If the virtual desktop is larger than the actual guest resolution, then the position at which the pointer is reported will be scaled, as the host reports a position relative to the physical resolution (was that understandable?) However, I can't find any way for the mouse driver to access this information (the graphics driver can, obviously, but the two don't communicate). The workaround is to make sure that the virtual desktop is no larger than the guest resolution.

I've implemented a better work-around for this situation. Now, if the virtual desktop in the guest is larger than the physical one we hide the host mouse pointer and let the guest draw its own pointer in software inside the VM. The guest will always draw the pointer where it thinks it ought to be. A slightly ugly solution, but still much better than before. Unfortunately this won't make it into the 2.1 series though.

Thank you for the update, Michael. I've worked around this for now by choosing different resolutions.