[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Qemu-devel] [Bug 1578192] Re: GTK+ interface doesn't translate keycodes

From: wyzu
Subject: [Qemu-devel] [Bug 1578192] Re: GTK+ interface doesn't translate keycodes properly with Wayland backend
Date: Fri, 06 May 2016 16:39:19 -0000

So here's my admittedly quick and dirty solution. This patch adds
support for evdev keycodes using translate_evdev_keycode when

Affected functions:

The caveat with this patch is that I don't see any good way to query
Wayland/libinput to find out if evdev is actually the backend. As of
now, evdev is the only backend supported, but others could be added in
the future. Since XFree86 is the only other keycode type Qemu supports
(and it is not supported by Wayland), I don't see any reason to check
for evdev on Wayland at this time.

One possibility might be libinput_device_get_udev_device and
udev_device_get_subsystem, but even then, GTK+ doesn't (yet) provide any
(documented) way to go from a GdkDevice to a struct libinput_device like
it does with gdk_x11_display_get_xdisplay and XkbGetKeyboard. See
We would also have to modify the configure script to link against
libinput in that case.

** Patch added: "gtk.c.patch"

You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.

  GTK+ interface doesn't translate keycodes properly with Wayland

Status in QEMU:

Bug description:
  I already posted this on the mailing list
  devel/2016-05/msg00119.html) but I decided to do a formal bug report
  so it can be tracked and doesn't get lost.

  ... I'm no expert, but it looks like GTK+ key events come in at the
  ui/gtk.c:gd_key_event callback function, which calls
  ui/gtk.c:gd_map_keycode to translate the GTK+ keycode into the Qemu
  keycode before sending it on using qemu_input_event_send_key_number.
  The problem is that gd_map_keycode is incomplete when GTK+ is running
  on a backend other than X11.

  static int gd_map_keycode(GtkDisplayState *s, GdkDisplay *dpy, int 
      int qemu_keycode;

      if (GDK_IS_WIN32_DISPLAY(dpy)) {
          qemu_keycode = MapVirtualKey(gdk_keycode, MAPVK_VK_TO_VSC);
          switch (qemu_keycode) {
          case 103:   /* alt gr */
              qemu_keycode = 56 | SCANCODE_GREY;
          return qemu_keycode;

      if (gdk_keycode < 9) {
          qemu_keycode = 0;
      } else if (gdk_keycode < 97) {
          qemu_keycode = gdk_keycode - 8;
  #ifdef GDK_WINDOWING_X11
      } else if (GDK_IS_X11_DISPLAY(dpy) && gdk_keycode < 158) {
          if (s->has_evdev) {
              qemu_keycode = translate_evdev_keycode(gdk_keycode - 97);
          } else {
              qemu_keycode = translate_xfree86_keycode(gdk_keycode - 97);
      } else if (gdk_keycode == 208) { /* Hiragana_Katakana */
          qemu_keycode = 0x70;
      } else if (gdk_keycode == 211) { /* backslash */
          qemu_keycode = 0x73;
      } else {
          qemu_keycode = 0;

      return qemu_keycode;

  In my case, I'm using GTK+'s Wayland backend, so keycodes 97 through
  157 (this includes KEY_HOME(102), KEY_PAGEUP(104), KEY_PAGEDOWN(109),
  KEY_END(107), etc.) are never translated into a qemu_keycode, and the
  final 'else' block is hit, causing gd_map_keycode to return 0, which
  is an invalid keycode and thus cannot be handled by xen-kbdfront. At
  least that's my best guess as to what is happening.

  The solution that comes to mind is provide an alternative to
  translate_{evdev,xfree86}_keycode that is compatable with
  Wayland/libinput, but I don't know exactly which API would provide
  this functionality, much less do I have a patch. Intuition tells me
  that translate_evdev_keycode would probably work under Wayland because
  Weston uses libinput which uses evdev as its backend, but I don't know
  this for a fact, and I don't know if it would be the Right Way (i.e.
  Wayland or libinput might provide an API for this purpose, but I don't

  I may try to do some testing with translate_evdev_keycode on Wayland
  and also look into any possible APIs for keycode translation, but I
  just wanted to put it out there and get some feedback awhile.

  Qemu 2.2.1 from Xen 4.6.1 (relevant code appears unchanged in Qemu master)
  GTK+ 3.18.7
  Wayland 1.9.0
  Weston 1.9.0
  libinput 1.2.3

To manage notifications about this bug go to:

reply via email to

[Prev in Thread] Current Thread [Next in Thread]