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[tobiaseigen]

Greetings,

I have two OLPC laptops in front of me that were purchased during the first G1G1 scheme in 2007. One of them is working as expected. The other one works fine except it does not (and apparently never has) connect to the wireless router although it does seem to see the other XO in the "mesh" network. The other one does not see the problem XO in the network, however. I have upgraded both to the latest 8.2.1 version of Sugar.

I would be grateful for help troubleshooting this problem - I have two days while visiting here with friends to get this problem sorted out.

Warm regards,

Tobias

[Dinky]

By update, you do mean clean install using USB drive, right ? The mesh and the internet connections use two different programs / protocols. This suggests software if the two XO's mesh with each other.  OOPS:  I read your post again and you are saying that the the troubled XO receives but does not transmit --- now we are talking hardware. I would suggest starting by checking the internal antenna connections (I believe one is transmit and the other is receive).  Unfortunately, this involves removing the back, which requires some diassembly to get at the screws under the display. By check, I mean unseat and reseat connectors. Swapping connections may provided further troubleshooting  --- perhaps to determine that the transmit hardware has failed (no repair). Any disassembly should be done with the power and battery removed.

Here is a disassembly video by anna --- stop before removing the display.  Pivoting the display up or down will allow access to screws about 1 1/2 inch in from each corner.  Removing these 4 screws releases the back cover.

****http://www.youtube.com/watch?v=JmUqRgvHI9o&feature=player_embedded***


The linux wifi test programs are in /sbin and are of the form iw*******.  Not all these work on the XO.  Do they give the same results on both XO's ?

Good starting command is iwconfig --- how does the "no ip XO" differ from the "ip XO" ?

[mavrothal]

tobiaseigen
do you see the wifi access points in the neighborhood view (the button with the 8 dots)?
Did you try to connect through the terminal (ifconfig eth0 up/iwlist eth0 scanning/iwlist eth0 essid "APname" key "<passwr>)? What are the messages? 
Besides a possible hardware/antenna issue that Dinky mentioned could also be the AP specially if it has WPA/WPA2 security (sounds crazy with two identical machines but is possible). Try an open or WEP network. Also make sure that mac address filtering is not enable in the AP by any chance or home networking with any strange settings.
If is not a hardware issue you may also want to try the F11 builds like os16 or os301. Have a newer network manager that works muck better. Keep in mind that they both need a developers key though.

[tobiaseigen]

Thanks Dinky and mavrothal - I really appreciate the help. To answer questions:

1) yes, we did a clean install using USB

2) yes, we do see the wifi access points in the neighborhood view.

3) I tried connecting through the terminal but don't understand the command to connect. I can do ifconfig eth0 up and then iwlist scanning to see all the access points.

I have an open access point that does not require a password - the other laptop connects fine, but this one does not. I click on it in neighborhood view and try to connect, and it says "connecting..." for a few minutes but then never connects. After a while it then gives an option to "Connect" again when on the other laptop it would say "Disconnect".

This does seem to point to a hardware problem of being able to receive but not to send. I will open it up and have a look. Any further advice much appreciated!

Thanks!

Tobias

[mavrothal]

3) I tried connecting through the terminal but don't understand the command to connect. I can do ifconfig eth0 up and then iwlist scanning to see all the access points.

Assuming that your access point is showing in your wlist scanning output as "essid home network" to connect in this (open) network, type

Code:

iwconfig eth0 essid "home network"

quotes are not necessary if it has a name without spaces but are no harm either way.
Also check which channel your AP is on. I _think_ that channels 1, 6 and 11 are OK.

[tobiaseigen]

thanks mavrothal - I tried "iwconfig eth0 essid tobias" but it fails quietly - no connection, but no error message. any thoughts on how to get troubleshooting info this way?

thanks!

tobias

[mavrothal]

thanks mavrothal - I tried "iwconfig eth0 essid tobias" but it fails quietly - no connection, but no error message. any thoughts on how to get troubleshooting info this way?

Network Manager should keep logs but I do not remember where right now. Check in /var/log.
Also try "dmesg | tail" after a failed connection and see what is there.

To test if it is a hardware or a software problem try to share an activity between the 2 XO. If you initiate sharing from the faulty XO and the activity shows up in the neighborhood other of the other it means that is transmitting OK.
Simpler yet, does the faulty XO shows up in the neighborhood of the good one the way the good one shows up in the neighborhood of the faulty? If not, open it up.

Edit: you can also try a hardware check from the open firmware. just press rocker left during boot

[tobiaseigen]

thanks mavrothal -

the dmesg shows the following (typed in so forgive errors!) which might give some clues - though I am not sure what to make of it:

usb8xxx: Firmware ready event received
libertas: 00:17:c4:14:35:06, fw 5.110.22p23 cap 0x0000003a3
libertas: eth0 Marvell WLAN 802.11 adapter
libertas: PREP_CMD: command 0x0074 failed: 2
usb8xxx: Firmware does not seem to support PS mode
usbcore: registered new interface driver usb8xxx

I did the hardware check but the messages just flashed by very fast on the screen and I did not see anything obvious.

Thanks for any advice,

Tobias

[tobiaseigen]

hi mavrothal - looks like this error has appeared before:

https://dev.laptop.org/ticket/8020

No real answers though. Might be related to this issue?

[tobiaseigen]

Dinky:

I would suggest starting by checking the internal antenna connections (I believe one is transmit and the other is receive).  Unfortunately, this involves removing the back, which requires some diassembly to get at the screws under the display. By check, I mean unseat and reseat connectors. Swapping connections may provided further troubleshooting  --- perhaps to determine that the transmit hardware has failed (no repair).

I have taken the XO apart and checked the black and grey wires - the black one seems to go to one antenna which then connects to the other one? The black wire was hard to unseat, and in the process I pulled a wire out of the connector. I then used pliers to reconnect the wire and seat it again. 

When I put everything back together and powered on the XO, it behaved exactly as it did before.

I am not clear on what you mean by "swapping connections" - can you explain?

Any other troubleshooting ideas?

Thanks!

Tobias

[Dinky]

The swapping connections (cables) was to catch any bad antenna wiring (connector, wire, or rabbit ear pivot connection).  There is enough play in the cable lengths to do this. This applies only if one antenna receives and one transmits. edit Finally found info on antenna --- no separate function -- transmit and receive on same antenna.  Can function on just one antenna, if one broken.   http://wiki.laptop.org/go/Wireless

I noted on the ticket reference, that the error occurred when all six were booted at the same time and rebooting solved problem.  The error message apparently applies to all XO's.  I sometimes (very rarely) had this problem if two XO's were booted at exactly the same time.  They did not see each other ; rebooting always solved the problem.  I  adopted the practice of booting one, waiting 30 sec and booting the other and have not seen the problem since.  Your problem seems more persistent.

I have no other suggestions -- mavrothal has been thorough.

[mavrothal]

Dobias
as I said in message #2 above install os16 or os301
They have newer firmware, newer Network manager, newer Sugar, newer Fedora (F11) and come with GNOME desktop too (see this tread). All they need is a developers key.
Try it. It may solve the problem if, as it looks, it may be a OFW/os issue.

[anna]

I've seen a few XOs where the wifi is just flat out flaky, no matter what I put on them.  They'll fail to connect, or if they do the connection is very weak and usually dies after a few minutes.  I'll do "ifconfig" and the eth0/msh0 devices will appear and disappear.  Eventually, these XOs won't even show any network devices at all.

In the cases I've seen, it's a hardware issue.  Unfortunately there's no way to get networking on those XOs unless you use a wifi or ethernet dongle.  And then that doesn't give you mesh, though of course you can go through a jabber server for collaboration.

Not to be a downer here, but don't be surprised if you can't get it to work.  Yes, it is very disappointing, but if the wifi chip has flaked out, there's nothing you can do.

[tobiaseigen]

thanks everyone for your input. I think Anna's description is spot on.

I'll let you know if I figure anything out at this point but I think it may not be worth continuing to try to get this XO working. 

-T