Re: [Qemu-devel] [PATCH] vnc: lift modifier keys on client disconnect.

[Peter Lieven]

Hi Gerd,

just looking at your patch. It works fine so far, but I am curious how
to handle the lock keys? I have the problem that if I press caps lock
and then create a new vnc session with exclusive access (from another
terminal), the caps lock is still there.

Wouldn't it be right to release at least also caps lock if not all lock
keys?

Peter

Gerd Hoffmann wrote:
> For any modifier key (shift, ctrl, alt) still pressed on disconnect
> inject a key-up event into the guest.  The vnc client is gone, it will
> not do that, so qemu has to do it instead.
>
> Without this keys will get stuck, making the guest act in weird ways
> after reconnecting.  Reproducer: exit vnc client via Alt-F4, guest
> continues to see the pressed alt key and will not react to key events
> in any useful way until you tap the alt key once to unstuck it.
>
> Signed-off-by: Gerd Hoffmann <address@hidden>
> ---
>  ui/vnc.c |   25 +++++++++++++++++++++++++
>  1 files changed, 25 insertions(+), 0 deletions(-)
>
> diff --git a/ui/vnc.c b/ui/vnc.c
> index 83a9b15..02b71bc 100644
> --- a/ui/vnc.c
> +++ b/ui/vnc.c
> @@ -46,6 +46,7 @@ static VncDisplay *vnc_display; /* needed for info vnc
> */
>  static DisplayChangeListener *dcl;
>
>  static int vnc_cursor_define(VncState *vs);
> +static void vnc_release_modifiers(VncState *vs);
>
>  static void vnc_set_share_mode(VncState *vs, VncShareMode mode)
>  {
> @@ -1051,6 +1052,7 @@ static void vnc_disconnect_finish(VncState *vs)
>      vnc_sasl_client_cleanup(vs);
>  #endif /* CONFIG_VNC_SASL */
>      audio_del(vs);
> +    vnc_release_modifiers(vs);
>
>      QTAILQ_REMOVE(&vs->vd->clients, vs, next);
>
> @@ -1679,6 +1681,29 @@ static void do_key_event(VncState *vs, int down,
> int keycode, int sym)
>      }
>  }
>
> +static void vnc_release_modifiers(VncState *vs)
> +{
> +    static const int keycodes[] = {
> +        /* shift, control, alt keys, both left & right */
> +        0x2a, 0x36, 0x1d, 0x9d, 0x38, 0xb8,
> +    };
> +    int i, keycode;
> +
> +    if (!is_graphic_console()) {
> +        return;
> +    }
> +    for (i = 0; i < ARRAY_SIZE(keycodes); i++) {
> +        keycode = keycodes[i];
> +        if (!vs->modifiers_state[keycode]) {
> +            continue;
> +        }
> +        if (keycode & SCANCODE_GREY) {
> +            kbd_put_keycode(SCANCODE_EMUL0);
> +        }
> +        kbd_put_keycode(keycode | SCANCODE_UP);
> +    }
> +}
> +
>  static void key_event(VncState *vs, int down, uint32_t sym)
>  {
>      int keycode;
> --
> 1.7.1
>
>
>