docs/multiseat.txt

   1
   2 multiseat howto (with some multihead coverage)
   3 ==============================================
   4
   5 host side
   6 ---------
   7
   8 First you must compile qemu with a user interface supporting
   9 multihead/multiseat and input event routing.  Right now this list is
  10 pretty short: sdl2.
  11
  12   ./configure --enable-sdl --with-sdlabi=2.0
  13
  14
  15 Next put together the qemu command line:
  16
  17 qemu    -enable-kvm -usb $memory $disk $whatever \
  18         -display sdl \
  19         -vga std \
  20         -device usb-tablet
  21
  22 That is it for the first head, which will use the standard vga, the
  23 standard ps/2 keyboard (implicitly there) and the usb-tablet.  Now the
  24 additional switches for the second head:
  25
  26         -device pci-bridge,addr=12.0,chassis_nr=2,id=head.2 \
  27         -device secondary-vga,bus=head.2,addr=02.0,id=video.2 \
  28         -device nec-usb-xhci,bus=head.2,addr=0f.0,id=usb.2 \
  29         -device usb-kbd,bus=usb.2.0,port=1,display=video.2 \
  30         -device usb-tablet,bus=usb.2.0,port=2,display=video.2
  31
  32 This places a pci bridge in slot 12, connects a display adapter and
  33 xhci (usb) controller to the bridge.  Then it adds a usb keyboard and
  34 usb mouse, both connected to the xhci and linked to the display.
  35
  36 The "display=video2" sets up the input routing.  Any input coming from
  37 the window which belongs to the video.2 display adapter will be routed
  38 to these input devices.
  39
  40
  41 guest side
  42 ----------
  43
  44 You need a pretty recent linux guest.  systemd with loginctl.  kernel
  45 3.14+ with CONFIG_DRM_BOCHS enabled.  Fedora 20 will do.  Must be
  46 fully updated for the new kernel though, i.e. the live iso doesn't cut
  47 it.
  48
  49 Now we'll have to configure the guest.  Boot and login.  "lspci -vt"
  50 should list the pci bridge with the display adapter and usb controller:
  51
  52     [root@fedora ~]# lspci -vt
  53     -[0000:00]-+-00.0  Intel Corporation 440FX - 82441FX PMC [Natoma]
  54                [ ... ]
  55                \-12.0-[01]--+-02.0  Device 1234:1111
  56                             \-0f.0  NEC Corporation USB 3.0 Host Controller
  57
  58 Good.  Now lets tell the system that the pci bridge and all devices
  59 below it belong to a separate seat by dropping a file into
  60 /etc/udev/rules.d:
  61
  62     [root@fedora ~]# cat /etc/udev/rules.d/70-qemu-autoseat.rules
  63     SUBSYSTEMS=="pci", DEVPATH=="*/0000:00:12.0", TAG+="seat", ENV{ID_AUTOSEAT}="1"
  64
  65 Reboot.  System should come up with two seats.  With loginctl you can
  66 check the configuration:
  67
  68     [root@fedora ~]# loginctl list-seats
  69     SEAT
  70     seat0
  71     seat-pci-pci-0000_00_12_0
  72
  73     2 seats listed.
  74
  75 You can use "loginctl seat-status seat-pci-pci-0000_00_12_0" to list
  76 the devices attached to the seat.
  77
  78 Background info is here:
  79   http://www.freedesktop.org/wiki/Software/systemd/multiseat/
  80
  81 Enjoy!
  82
  83 --
  84 Gerd Hoffmann <kraxel@redhat.com>