#10878 NORM Not Tri: Aggressive power management hindering XO collaboration

[Zarro Boogs per Child]

#10878: Aggressive power management hindering XO collaboration
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           Reporter:  sridhar       |       Owner:                                         
               Type:  defect        |      Status:  new                                    
           Priority:  normal        |   Milestone:  Not Triaged                            
          Component:  not assigned  |     Version:  1.5/1.0 Software Build os860 aka 10.1.3
         Resolution:                |    Keywords:                                         
        Next_action:  never set     |    Verified:  0                                      
Deployment_affected:                |   Blockedby:                                         
           Blocking:                |  
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Comment(by greenfeld):

 This is wild speculation, but how long are the kids waiting between turns
 before the connection stalls?

 Something I've noticed previously with XO laptops is that they do not seem
 configured to wake up on ARP requests.  If a system knows an XO's Ethernet
 address<->IP mapping it can wake the XO up with unicast data; but if it
 doesn't know the mapping the XO will never respond.

 So if the TCP connection between the school server and the laptop is not
 kept alive with  keepalives or data before it dies, or if the ARP entry
 expires out of the ARP cache for some reason, no system may know how to
 contact the XO.

 The downside to waking up to ARP requests is that XOs are likely to wake
 up significantly more often, if they can get to suspend mode at all.

 In any case, running tcpdump on a schoolserver on the network interface
 with the XOs to obtain a packet capture while reproducing this issue might
 be useful.

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Ticket URL: <http://dev.laptop.org/ticket/10878#comment:6>
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