51 lines
		
	
	
		
			1.8 KiB
		
	
	
	
		
			ReStructuredText
		
	
	
	
	
	
		
		
			
		
	
	
			51 lines
		
	
	
		
			1.8 KiB
		
	
	
	
		
			ReStructuredText
		
	
	
	
	
	
| 
								 | 
							
								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
							 | 
						||
| 
								 | 
							
								======= ===============================================================
							 |