vnc: Set default kbd delay to 10ms

The current VNC default keyboard delay is 1ms. With that we're constantly
typing faster than the guest receives keyboard events from an XHCI attached
USB HID device.

The default keyboard delay time in the input layer however is 10ms. I don't know
how that number came to be, but empirical tests on some OpenQA driven ARM
systems show that 10ms really is a reasonable default number for the delay.

This patch moves the VNC delay also to 10ms. That way our default is much
safer (good!) and also consistent with the input layer default (also good!).

Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1499863425-103133-1-git-send-email-agraf@suse.de
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
(cherry picked from commit d3b0db6dfea6b3a9ee0d96aceb796bdcafa84314)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

qemu-options.hx

@@ -1491,7 +1491,7 @@ spec but is traditional QEMU behavior.
 @item key-delay-ms
 
 Set keyboard delay, for key down and key up events, in milliseconds.
-Default is 1.  Keyboards are low-bandwidth devices, so this slowdown
+Default is 10.  Keyboards are low-bandwidth devices, so this slowdown
 can help the device and guest to keep up and not lose events in case
 events are arriving in bulk.  Possible causes for the latter are flaky
 network connections, or scripts for automated testing.

ui/vnc.c

@@ -3811,7 +3811,7 @@ void vnc_display_open(const char *id, Error **errp)
     }
 
     lock_key_sync = qemu_opt_get_bool(opts, "lock-key-sync", true);
-    key_delay_ms = qemu_opt_get_number(opts, "key-delay-ms", 1);
+    key_delay_ms = qemu_opt_get_number(opts, "key-delay-ms", 10);
     sasl = qemu_opt_get_bool(opts, "sasl", false);
 #ifndef CONFIG_VNC_SASL
     if (sasl) {