Hello Gerd, 14.12.2016 11:11, Gerd Hoffmann wrote: >> So I would be interested to know whether anyone else has thought about >> this problem, and possibly even about an interface to let the compositor >> pass the information. If not, would people be open to the idea? I >> would much rather have something generally agreed on than hack something up. > > I think the best way to tackle this is to have multiple tablets, one per > display device (touchscreen-style setup). > > qemu can do that, with input routing (must configure on the host which > display belongs to which tablet). Here is some info on that: > > http://git.qemu-project.org/?p=qemu.git;a=blob;f=docs/multiseat.txt;hb=HEAD > > The setup on the guest side is completely manual. You have to use > "xinput --map-to-output" to tell Xorg which tablet belongs to which > display. Maybe it is also possible to stick that into xorg.conf. > Should be improved, and it surely makes sense that qemu and virtualbox > use the same approach here. > > Not sure if and how this works automatically with physical touchscreens. > Any clues are welcome.
Thanks for the answer. That was the direction I was initially expecting to go too. In theory libinput lets you map input devices to heads[1] using a udev property[2], though I have yet to test whether anyone supports that yet (couldn't find it in the Mutter/GNOME Shell source, but I'm not familiar with it). As the API description says, the default without that property is still to map the input device to all screens like X.Org on Linux does. [1] https://cgit.freedesktop.org/wayland/libinput/tree/src/udev-seat.c?id=1.5.3#n97 [2] https://wayland.freedesktop.org/libinput/doc/0.99.1/group__device.html#gaf48626f6190e9c9bc14abb704e66cc22 > Another option is to use a guest agent, spice does that since years to > handle multihead. The guest agent queries the display layout using > xrandr, gets x + y + displayid from the spice client and generates > pointer events from that. But I expect that scheme breaks with wayland > because wayland is by design alot more restrictive, so spice-agent > probably isn't allowed to send pointer events. So not really an option > these days ... We actually do something similar in Windows guests: older versions provided the layout information to the driver directly, but at least Windows 10 does not, so we query it with a user-space agent which passes it to the driver. (We send our pointer events from a driver, in all supported guest types, which works fine with Wayland too.) It would be nice though as I said if the compositor (or whoever is controlling the display) could just provide the layout information to the driver itself. We already have "suggested X" and "suggested Y" for the other direction, and for now I have solved it by always providing "suggested X" and "suggested Y" hints in the driver. That which works well enough in a first approximation - if the user changes the layout inside the virtual machine the mapping breaks, and as soon as they change it outside it mends again. So my idea was to try to have people agree on on interface for that. Regards Michael > cheers, > Gerd -- Michael Thayer | VirtualBox engineer ORACLE Deutschland B.V. & Co. KG | Werkstr. 24 | D-71384 Weinstadt ORACLE Deutschland B.V. & Co. KG Hauptverwaltung: RiesstraÃe 25, D-80992 München Registergericht: Amtsgericht München, HRA 95603 Komplementärin: ORACLE Deutschland Verwaltung B.V. Hertogswetering 163/167, 3543 AS Utrecht, Niederlande Handelsregister der Handelskammer Midden-Nederland, Nr. 30143697 Geschäftsführer: Alexander van der Ven, Jan Schultheiss, Val Maher
