Bugzilla – Bug 359945
cursor acceleration problem in “qemu -vnc”
Last modified: 2008-07-14 08:19:38 UTC
I started qemu like this: sudo qemu-kvm -no-quit -m 512 \ -cdrom /dist/install/openSUSE-11.0-Alpha2/openSUSE-11.0-Alpha2-DVD-x86_64.iso \ -boot d \ -hda $NAME.img \ -monitor stdio \ -net nic,model=rtl8139 \ -net user,hostname=$NAME \ -vnc :2 \ $@ and then connected to the vncserver with vncviewer :2 The mouse cursor *inside* the viewer window (white arrow during the installation with YaST) and the cursor hovering over vncviewer window (black dot by default) get out of sync when the mouse is moved fast, i.e. they can be at completely different positions when the mouse stops moving and they stay there. After opening an xterm and executing xset m 1 (disables mouse acceleration), the problem goes away. If the two cursors are still at different positions because of the problem mentioned above, they can be synchronized by moving the mouse to the lower right corner. After doing this synchronization once, the two cursors stay synchronized.
Maybe mouse acceleration off should be the default because this behaviour that the cursors get out of sync with mouse acceleration on is very confusing. Reassign to qemu maintainer.
Alexander Graf suggested to try the options -usb -usbdevice tablet for qemu. This didn’t help, the cursors were still out of sync. *And* ‘xset m 1’ could not be used anymore as a workaround, even after a ‘xset m 1’ the cursors stayed out of sync.
Reassigning to _kvm_ maintainer. (I would assume the same problem to exist in qemu proper, though.)
Ulrich Hecht> (I would assume the same problem to exist in qemu Ulrich Hecht> proper, though.) Yes, it happens the same way when starting qemu like this (without any kernel module): qemu-system-x86_64 -std-vga -no-quit -m 512 \ -cdrom /mounts/dist/install/openSUSE-11.0-Alpha2/openSUSE-11.0-Alpha2-DVD-x86_64.iso \ -boot d \ -hda $NAME.img \ -monitor stdio \ -net nic,model=rtl8139 \ -net user,hostname=$NAME \ -vnc :2 \ $@ I know that no kernel module is used because of: Could not open '/dev/kqemu' - QEMU acceleration layer not activated: No such file or directory
Mouse acceleration is always broken with VNC. VNC only knows about absolute positioning, while a mouse only knows how to move relatively. Converting these two is simply broken by design. One way around this is to use the "vmmouse" driver instead of the "mouse" driver in xorg.conf, if you're in a VM. This way the VMware backdoor driver for absolute mouse positioning is used and you can use -vnc just fine.
So sax2 should use the vmmouse driver automatically if the system is running inside qemu? Sorry, "configure it by hand", especially if there is no way to configure it short of using the "vi" configuration tool, is no solution for features as important as virtualization.
*** This bug has been marked as a duplicate of bug 372189 ***