From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:47250) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1URlUi-0000G0-MT for qemu-devel@nongnu.org; Mon, 15 Apr 2013 11:39:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1URlUd-0006mX-HG for qemu-devel@nongnu.org; Mon, 15 Apr 2013 11:39:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:23433) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1URlUd-0006mB-8k for qemu-devel@nongnu.org; Mon, 15 Apr 2013 11:38:55 -0400 Message-ID: <516C1F06.10909@redhat.com> Date: Mon, 15 Apr 2013 17:38:46 +0200 From: Gerd Hoffmann MIME-Version: 1.0 References: <1365426454-6723-1-git-send-email-lilei@linux.vnet.ibm.com> <516BF534.3000909@redhat.com> <87wqs3g8ke.fsf@codemonkey.ws> In-Reply-To: <87wqs3g8ke.fsf@codemonkey.ws> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] Support for VNC LED state extension proposal List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: lagarcia@br.ibm.com, Lei Li , qemu-devel@nongnu.org On 04/15/13 16:41, Anthony Liguori wrote: > Gerd Hoffmann writes: > >> Hi, >> >>> When access a guest by console through VNC, there might be >>> mismatch between the lock keys notification LED on the computer >>> running the VNC client session and the current status of the lock >>> keys on the guest machine. This happens because the VNC protocol >>> does not have any support to deal with setting led state. >> >> What is the exact issue you are trying to fix here? >> >> The vnc server code in qemu already tracks the keyboard led state and >> will insert synthetic key events if needed to make sure vnc client and >> guest machine stay in sync. > > If the guest changes LED state, we want to the client to update the > physical keyboard LED state. Guests usually change the LED state in response to a keyboard event, in which case the physical keyboard LEDs already have the correct state. There are exceptions of course. Guest linux kernel panic-ing, then blinking capslock. Multiple vnc clients connected at the same time. > Think thin client without an X server. Should be even less an issue there. With X & multiple windows guest+host capslock/numlock state go out of sync because of sequences like move-kbd-focus-away-from-vncclient-window + press-{caps,num}lock + move-focus-back (and thats why we have the logic to insert synthetic key events to resync in the first place). What is your vnc client? Does it support VNC_ENCODING_EXT_KEY_EVENT? cheers, Gerd