From 7504ae690c7320f3852890974708795cf5469895 Mon Sep 17 00:00:00 2001 From: Lei Li Date: Thu, 25 Apr 2013 13:29:12 +0800 Subject: [PATCH] doc: document the Pseudo-encoding of LED state Signed-off-by: Lei Li Reviewed-by: Anthony Liguori Message-id: 1366867752-11578-5-git-send-email-lilei@linux.vnet.ibm.com Signed-off-by: Anthony Liguori --- docs/vnc-ledstate-Pseudo-encoding.txt | 50 +++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 docs/vnc-ledstate-Pseudo-encoding.txt diff --git a/docs/vnc-ledstate-Pseudo-encoding.txt b/docs/vnc-ledstate-Pseudo-encoding.txt new file mode 100644 index 0000000000..0f124f68b1 --- /dev/null +++ b/docs/vnc-ledstate-Pseudo-encoding.txt @@ -0,0 +1,50 @@ +VNC LED state Pseudo-encoding +============================= + +Introduction +------------ + +This document describes the Pseudo-encoding of LED state for RFB which +is the protocol used in VNC as reference link below: + +http://tigervnc.svn.sourceforge.net/viewvc/tigervnc/rfbproto/rfbproto.rst?content-type=text/plain + +When accessing 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. + +To solve this problem it attempts to add LED state Pseudo-encoding +extension to VNC protocol to deal with setting LED state. + +Pseudo-encoding +--------------- + +This Pseudo-encoding requested by client declares to server that it supports +LED state extensions to the protocol. + +The Pseudo-encoding number for LED state defined as: + +======= =============================================================== +Number Name +======= =============================================================== +-261 'LED state Pseudo-encoding' +======= =============================================================== + +LED state Pseudo-encoding +-------------------------- + +The LED state Pseudo-encoding describes the encoding of LED state which +consists of 3 bits, from left to right each bit represents the Caps, Num, +and Scroll lock key respectively. '1' indicates that the LED should be +on and '0' should be off. + +Some example encodings for it as following: + +======= =============================================================== +Code Description +======= =============================================================== +100 CapsLock is on, NumLock and ScrollLock are off +010 NumLock is on, CapsLock and ScrollLock are off +111 CapsLock, NumLock and ScrollLock are on +======= ===============================================================