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

[Daniel Berrange]

This issue was fixed already in git master with:

commit a8ffb372a2202c65f42fdb69891ea68a2f274b55
Author: Daniel P. Berrange <address@hidden>
Date:   Thu Dec 1 09:41:17 2016 +0000

    ui: use evdev keymap when running under wayland
    
    Wayland always uses evdev as its input source, so QEMU
    can use the existing evdev keymap data
    
    Signed-off-by: Daniel P. Berrange <address@hidden>
    Tested-by: Stefan Hajnoczi <address@hidden>
    Message-id: address@hidden
    Signed-off-by: Gerd Hoffmann <address@hidden>


** Changed in: qemu
       Status: New => Fix Committed

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https://bugs.launchpad.net/bugs/1578192

Title:
  GTK+ interface doesn't translate keycodes properly with Wayland
  backend

Status in QEMU:
  Fix Committed

Bug description:
  I already posted this on the mailing list
  (https://lists.nongnu.org/archive/html/qemu-
  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 
gdk_keycode)
  {
      int qemu_keycode;

  #ifdef GDK_WINDOWING_WIN32
      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;
              break;
          }
          return qemu_keycode;
      }
  #endif

      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);
          }
  #endif
      } 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
  know).

  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

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