Re: [Qemu-devel] [PATCH] vnc: add configurable keyboard delay

[Laurent Vivier <lvivier@redhat.com>]

On 23/05/2016 15:19, Gerd Hoffmann wrote:
> Limits the rate kbd events from the vnc server are forwarded to the
> guest, so input devices which are typically low-bandwidth can keep
> up even on bulky input.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  ui/vnc.c | 13 +++++++++++--
>  ui/vnc.h |  1 +
>  2 files changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/ui/vnc.c b/ui/vnc.c
> index d2ebf1f..ea3b3d4 100644
> --- a/ui/vnc.c
> +++ b/ui/vnc.c
> @@ -1629,6 +1629,7 @@ static void reset_keys(VncState *vs)
>      for(i = 0; i < 256; i++) {
>          if (vs->modifiers_state[i]) {
>              qemu_input_event_send_key_number(vs->vd->dcl.con, i, false);
> +            qemu_input_event_send_key_delay(vs->vd->key_delay_ms);
>              vs->modifiers_state[i] = 0;
>          }
>      }
> @@ -1638,9 +1639,9 @@ static void press_key(VncState *vs, int keysym)
>  {
>      int keycode = keysym2scancode(vs->vd->kbd_layout, keysym) & SCANCODE_KEYMASK;
>      qemu_input_event_send_key_number(vs->vd->dcl.con, keycode, true);
> -    qemu_input_event_send_key_delay(0);
> +    qemu_input_event_send_key_delay(vs->vd->key_delay_ms);
>      qemu_input_event_send_key_number(vs->vd->dcl.con, keycode, false);
> -    qemu_input_event_send_key_delay(0);
> +    qemu_input_event_send_key_delay(vs->vd->key_delay_ms);
>  }
>  
>  static int current_led_state(VncState *vs)
> @@ -1792,6 +1793,7 @@ static void do_key_event(VncState *vs, int down, int keycode, int sym)
>  
>      if (qemu_console_is_graphic(NULL)) {
>          qemu_input_event_send_key_number(vs->vd->dcl.con, keycode, down);
> +        qemu_input_event_send_key_delay(vs->vd->key_delay_ms);
>      } else {
>          bool numlock = vs->modifiers_state[0x45];
>          bool control = (vs->modifiers_state[0x1d] ||
> @@ -1913,6 +1915,7 @@ static void vnc_release_modifiers(VncState *vs)
>              continue;
>          }
>          qemu_input_event_send_key_number(vs->vd->dcl.con, keycode, false);
> +        qemu_input_event_send_key_delay(vs->vd->key_delay_ms);
>      }
>  }
>  
> @@ -3249,6 +3252,9 @@ static QemuOptsList qemu_vnc_opts = {
>              .name = "lock-key-sync",
>              .type = QEMU_OPT_BOOL,
>          },{
> +            .name = "key-delay-ms",
> +            .type = QEMU_OPT_NUMBER,
> +        },{
>              .name = "sasl",
>              .type = QEMU_OPT_BOOL,
>          },{
> @@ -3486,6 +3492,7 @@ void vnc_display_open(const char *id, Error **errp)
>  #endif
>      int acl = 0;
>      int lock_key_sync = 1;
> +    int key_delay_ms;
>  
>      if (!vs) {
>          error_setg(errp, "VNC display not active");
> @@ -3604,6 +3611,7 @@ void vnc_display_open(const char *id, Error **errp)
>  
>      reverse = qemu_opt_get_bool(opts, "reverse", false);
>      lock_key_sync = qemu_opt_get_bool(opts, "lock-key-sync", true);
> +    key_delay_ms = qemu_opt_get_number(opts, "key-delay-ms", 1);

Why the default value is 1 and not 0?
(Are there some impacts on the "qemu_input_event_send_key_delay(0);" you
replace above?)

Laurent
>      sasl = qemu_opt_get_bool(opts, "sasl", false);
>  #ifndef CONFIG_VNC_SASL
>      if (sasl) {
> @@ -3735,6 +3743,7 @@ void vnc_display_open(const char *id, Error **errp)
>      }
>  #endif
>      vs->lock_key_sync = lock_key_sync;
> +    vs->key_delay_ms = key_delay_ms;
>  
>      device_id = qemu_opt_get(opts, "display");
>      if (device_id) {
> diff --git a/ui/vnc.h b/ui/vnc.h
> index 81a3261..6568bca 100644
> --- a/ui/vnc.h
> +++ b/ui/vnc.h
> @@ -155,6 +155,7 @@ struct VncDisplay
>      DisplayChangeListener dcl;
>      kbd_layout_t *kbd_layout;
>      int lock_key_sync;
> +    int key_delay_ms;
>      QemuMutex mutex;
>  
>      QEMUCursor *cursor;
>