fix mouse tracking in VNC

[price]

In X over VNC, the cursor doesn't track the user's own cursor one-to-one. There's said to be a fix, running "xset m 1 1". We should (a) test this, (b) put it in the autoinstall images, and (c) document it for users running their own installers.

[andersk]

"xset m 1 1" is a kludge that might kind of work for a little while once you've moved your mouse around to all the right corners of the screen. The real solution is to give the guest a tablet device (usbdevice='tablet') that directly exposes absolute pointer coordinates.

[quentin]

"xset m 1 1" disables mouse acceleration. That causes the deltas from the remote mouse to directly affect the pointer. The VNC server keeps track of the cursor position, so it actually works pretty reliably once set.

Note that this is only temporary; we should figure out the equivalent lines to put in the X configuration.

I agree that tablet devices would be good if we can get them working, but I don't know if we can on every platform. We should still document it for people using their own distributions.

[price]

From the man page, "xset m 1" suffices. It looks like we want to put that line in a file in /etc/X11/Xsession.d/, and then it'll get run at X startup.

(Haven't yet tested this.)

[quentin]

We expose a tablet device now.