#9535 HIGH 1.5-sof: Need wake-on-WLAN support

Zarro Boogs per Child bugtracker at laptop.org
Thu Mar 25 17:38:21 EDT 2010


#9535: Need wake-on-WLAN support
-------------------------------------+--------------------------------------
           Reporter:  cjb            |       Owner:  dsaxena           
               Type:  defect         |      Status:  new               
           Priority:  high           |   Milestone:  1.5-software-later
          Component:  kernel         |     Version:  not specified     
         Resolution:                 |    Keywords:                    
        Next_action:  test in build  |    Verified:  0                 
Deployment_affected:                 |   Blockedby:                    
           Blocking:                 |  
-------------------------------------+--------------------------------------

Comment(by Quozl):

 Replying to [comment:23 pgf]:
 > how is a laptop informed that new chat messages are available?  (i.e.,
 who owns the protocol transaction?)

 It seems either laptop may own this duty, it is not clear from what I see.

 Chat activity on the wire consists of Clique packets.  I'm not sure what
 Clique means, but it is text in every packet exchanged.  They are UDP
 multicast packets.  Presumably because in the absence of a Telepathy
 Gabble we are instead using Telepathy Salut.

 When the host is suspended, the Clique packets from the peer do not wake
 it, and are lost.  They are not queued.  They don't appear on the network
 interface on resume.

 When the host wakes, within three seconds it sends a Clique packet.  Or it
 receives a Clique packet from the other participants.  It isn't clear
 which happens first.

 The packets probably contain some sequence numbering or something, I'm not
 sure.

 In response to a Clique packet from the newly woken host, the peer sends
 the line of chat again.

 It means both the peer and the host have to be not suspended for enough
 time for the chat to catch up.  If the host is woken to send text, and
 suspends before the peer is woken, then the message is not seen by the
 peer.

 The line of chat itself is XML.  306 bytes for the word "ok".  And as a
 bonus you get it in HTML as well.

 {{{
 <?xml version="1.0" encoding="UTF-8"?>
 <message from="b697ac9f at xo-a7-2a-5a"
 to="5c329a272168bdba1b45969005f787a30f7e81c9" type="groupchat">
 <body>ok</body>
 <html xmlns="http://jabber.org/protocol/xhtml-im">
 <body xmlns="http://www.w3.org/1999/xhtml">ok</body>
 </html>
 </message>
 }}}

 Method of discovery: ran tcpdump on both laptops in a Terminal and
 analysed the output after the event of interest.  The tcpdump command was:
 {{{
 tcpdump -i eth0 -n -s 0 -p -X
 }}}

-- 
Ticket URL: <http://dev.laptop.org/ticket/9535#comment:24>
One Laptop Per Child <http://laptop.org/>
OLPC bug tracking system


More information about the Bugs mailing list