7ewis
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Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 12:05 pm

Hi,

I have the Edimax EW-7811UN Wi-Fi adapter for my Pi, and it has worked well. But I haven't used my Pi for quite a while, but now I have some time off, I wanted to start playing with it again. I flashed the latest Raspbian and setup Wi-Fi, and it was working, but then it started to become very slow.

Eventually it just stopped, and I cannot get it to work at all now. The blue light may flash a few times initially, but after that - nothing.

I haven't changed any configuration, as I only flashed the card yesterday!

I did Google it and have surprisingly seen quite a few different problems with it, even though I've seen it recommended in many places.

Is this a new problem with Raspbian or something? Why doesn't it work? Obviously I can use Ethernet, but it's not very practical for me.

Has this happened to yours? Have you found a fix?
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DougieLawson
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 12:51 pm

Get your RPi connected with a wire to your router.
sudo apt-get update
sudo apt-get dist-upgrade
sudo rpi-update
Reboot
Disconnect the wire and try again with wireless.
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7ewis
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 12:56 pm

DougieLawson wrote:Get your RPi connected with a wire to your router.
sudo apt-get update
sudo apt-get dist-upgrade
sudo rpi-update
Reboot
Disconnect the wire and try again with wireless.
I'll try it, but what does dist-upgrade and rpi-update actually do?

It was the latest image from the site, and I did the update is raspy-config, and I did apt-get update and apt-get upgrade.

It worked on previous versions without any problems at all.

I did just test it on a Windows computer, and it worked. So it must be the Pi. I'm hoping your solution works!
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DougieLawson
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 12:59 pm

That will
a) update all installed packages
b) install the latest linux kernel & driver modules
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7ewis
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 1:57 pm

DougieLawson wrote:That will
a) update all installed packages
b) install the latest linux kernel & driver modules
I'm about to try that, I don't fully understand how SSH works, but I get a new fingerprint every time the IP changes, and have now been presented with this...

xxx-mbp:~ xxx$ ssh [email protected]ypi
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
The RSA host key for raspberrypi has changed,
and the key for the corresponding IP address 192.168.x.xx
is unknown. This could either mean that
DNS SPOOFING is happening or the IP address for the host
and its host key have changed at the same time.
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx.
Please contact your system administrator.
Add correct host key in /Users/xxx/.ssh/known_hosts to get rid of this message.
Offending RSA key in /Users/xxx/.ssh/known_hosts:2
RSA host key for raspberrypi has changed and you have requested strict checking.
Host key verification failed.

As I'm on my locked down WPA2 home network, where no one else can connect to unless they're inside my house, I highly doubt it's a MITM attack. (Although my router password may have changed recently, by itself... or I changed something by accident)
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DougieLawson
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 2:52 pm

Don't worry about those messages. They're just a feature of updating sshd while you're using it.
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7ewis
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 3:32 pm

DougieLawson wrote:Don't worry about those messages. They're just a feature of updating sshd while you're using it.
Okay.

I did the updates, and unfortunately it still isn't working correctly. Unplugging and then plugging back in again sometimes makes it flash a few times, then it stops.

But, if the Ethernet cable is connected, the Wi-FI works too!? If I do ifconfig I get an IP address for eth0 and wlan0... Then if I unplug the ethernet cable wlan0 goes off too.

It seems like the adapter is functioning okay, there must be a bug with it in this firmware maybe?

Edit: Going to try to add some more info to help diagnostics.

Code: Select all

[email protected] ~ $ lsusb
Bus 001 Device 002: ID 0424:9512 Standard Microsystems Corp. 
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. 
Bus 001 Device 004: ID 7392:7811 Edimax Technology Co., Ltd EW-7811Un 802.11n Wireless Adapter [Realtek RTL8188CUS]

Code: Select all

[email protected] ~ $ ifconfig
eth0      Link encap:Ethernet  HWaddr xx:xx:xx:xx:xx:xx  
          inet addr:192.168.1.92  Bcast:192.168.1.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:181 errors:0 dropped:1 overruns:0 frame:0
          TX packets:103 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:17990 (17.5 KiB)  TX bytes:14300 (13.9 KiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:8 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:1104 (1.0 KiB)  TX bytes:1104 (1.0 KiB)

wlan0     Link encap:Ethernet  HWaddr xx:xx:xx:xx:xx:xx  
          inet addr:192.168.1.93  Bcast:192.168.1.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:21 errors:0 dropped:0 overruns:0 frame:0
          TX packets:5 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:3238 (3.1 KiB)  TX bytes:1126 (1.0 KiB)
Last edited by 7ewis on Tue Dec 24, 2013 3:46 pm, edited 1 time in total.
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obcd
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 3:45 pm

If you have both ethernet and wifi connected to the same subnet, isn't it using the wired connection for it's communication? In such case, it might get it's dhcp for the wifi adapter trough the cable.

7ewis
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 3:47 pm

obcd wrote:If you have both ethernet and wifi connected to the same subnet, isn't it using the wired connection for it's communication? In such case, it might get it's dhcp for the wifi adapter trough the cable.
I'm not sure to be honest, I edited the post above with ifconfig, does that show anything?
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MrEngman
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 3:50 pm

Might be an idea to post the contents of file /etc/network/interfaces and if you use wpa_supplicant the contents of /etc/wpa_supplicant/wpa_supplicant.conf as well, so we can see how the networking is configured in case there's a problem with the configuration.


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7ewis
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 3:53 pm

MrEngman wrote:Might be an idea to post the contents of file /etc/network/interfaces and if you use wpa_supplicant the contents of /etc/wpa_supplicant/wpa_supplicant.conf as well, so we can see how the networking is configured in case there's a problem with the configuration.


MrEngman
Was just in the process of getting it! Here it is:

Code: Select all

/etc/network/interfaces
auto lo

iface lo inet loopback
iface eth0 inet dhcp

allow-hotplug wlan0
iface wlan0 inet manual
wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
iface default inet dhcp

Code: Select all

/etc/wpa_supplicant/wpa_supplicant.conf
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
        ssid="Mum use this one"
        psk="xxxxx"
        proto=RSN
        key_mgmt=WPA-PSK
        pairwise=TKIP
        auth_alg=OPEN
        priority=80
}


Edit: I really don't know why it doesn't work, it used to before on all older versions of Raspbian. It can't be a power/SD card issue, as it's the same Class 10 SD that I have used before, and it can't be a power issue, as it's the only USB device connected, and it's running off of a 1A 5V Apple power supply.
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MrEngman
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 4:10 pm

Hi,

I've seen some issues with wpa_supplicant.conf when updating/upgrading when there appeared to be a problem with the pairwise setting where the original setting that worked before the update had to be changed to get it back working. Weird and I've no idea why.

You could try changing pairwise=TKIP to pairwise=CCMP

As an alternative you could try with wpa_supplicant.conf set as follows

Code: Select all

/etc/wpa_supplicant/wpa_supplicant.conf
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
        ssid="Mum use this one"
        psk="xxxxx"
}
I know it looks odd but wpa_supplicant will work out the other settings for itself.

I don't normally use wpa_supplicant but when I do I mostly use the above format to avoid issues. Keep It Simple etc. ;)


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DougieLawson
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 4:28 pm

Add
auto wlan0
to /e*/n*/interfaces
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Richard-TX
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 4:29 pm

I have seen a great many WiFI mini dongles fail. Some in hours, some in days and some in a few months. Eventually all of the ones I bought failed. I have written off all the small dongles and only use the bigger bulkier wifi adapters.
Richard
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7ewis
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 4:36 pm

MrEngman wrote:Hi,

I've seen some issues with wpa_supplicant.conf when updating/upgrading when there appeared to be a problem with the pairwise setting where the original setting that worked before the update had to be changed to get it back working. Weird and I've no idea why.

You could try changing pairwise=TKIP to pairwise=CCMP

As an alternative you could try with wpa_supplicant.conf set as follows

Code: Select all

/etc/wpa_supplicant/wpa_supplicant.conf
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
        ssid="Mum use this one"
        psk="xxxxx"
}
I know it looks odd but wpa_supplicant will work out the other settings for itself.

I don't normally use wpa_supplicant but when I do I mostly use the above format to avoid issues. Keep It Simple etc. ;)


MrEngman
I just tried the TKIP to CCMP change, and now the adapter is flashing blue, but it doesn't appear if I do a 'arp -a'. It does appear in my routers online list though, so I tried SSHing into it from the IP my router says it's using, and.... I was about to write it times out, but after 2mins it actually connected over SSH?

Not sure why it would take that long, it's been turned on for at least 5 minutes with the CCMP change, and the Wi-Fi has only just started working.

Not sure if this is a 'fix' or not... Guess I'll try rebooting.
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7ewis
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 4:37 pm

DougieLawson wrote:Add
auto wlan0
to /e*/n*/interfaces
Does it need to go on any particular line or position?
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 4:38 pm

7ewis wrote:
DougieLawson wrote:Add
auto wlan0
to /e*/n*/interfaces
Does it need to go on any particular line or position?
First line is where it is in my version.
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7ewis
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 4:39 pm

Richard-TX wrote:I have seen a great many WiFI mini dongles fail. Some in hours, some in days and some in a few months. Eventually all of the ones I bought failed. I have written off all the small dongles and only use the bigger bulkier wifi adapters.
I thought it must have been the adapter, but it works in my Windows PC, just not my Pi.

It is almost a year old though.
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 4:41 pm

7ewis wrote:
Richard-TX wrote:I have seen a great many WiFI mini dongles fail. Some in hours, some in days and some in a few months. Eventually all of the ones I bought failed. I have written off all the small dongles and only use the bigger bulkier wifi adapters.
I thought it must have been the adapter, but it works in my Windows PC, just not my Pi.

It is almost a year old though.
It could be due to lack of grunt from your power supply.
Note: Any requirement to use a crystal ball or mind reading will result in me ignoring your question.

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7ewis
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 4:47 pm

DougieLawson wrote:
7ewis wrote:
Richard-TX wrote:I have seen a great many WiFI mini dongles fail. Some in hours, some in days and some in a few months. Eventually all of the ones I bought failed. I have written off all the small dongles and only use the bigger bulkier wifi adapters.
I thought it must have been the adapter, but it works in my Windows PC, just not my Pi.

It is almost a year old though.
It could be due to lack of grunt from your power supply.
After doing the change I mentioned above, it is working albeit very slowly.

It's just so strange because literally the only thing different since I first got it, is the OS. I have always used the same Pi, SD, Power, even the same leads!

I do have my Nexus 5 charger which is 1.2A, I could give that a go, but I really don't know why it should require more power than it did last year?
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7ewis
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 4:51 pm

MrEngman wrote: You could try changing pairwise=TKIP to pairwise=CCMP
MrEngman
After a reboot, it seems to be working still after doing this. But it just seems slower than normal?

Haven't tried unplugged it yet, I'll try a shutdown now and move it somewhere else and see if it's still working.
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MrEngman
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 5:50 pm

7ewis wrote:
MrEngman wrote: You could try changing pairwise=TKIP to pairwise=CCMP
MrEngman
After a reboot, it seems to be working still after doing this. But it just seems slower than normal?

Haven't tried unplugged it yet, I'll try a shutdown now and move it somewhere else and see if it's still working.
You could always try the cut down version of wpa_supplicant.conf I suggested and see how that behaves. wpa_supplicant will then sort out the parameters it needs itself.

I think I can say I've tried every single update of raspbian, about 120 different versions using rpi-update since 3.6.11+ appeared, as I try to keep the rtl8188eu wifi driver, for the TP-LINK TL-WN725N V2, up to date and have never seen any major problems, although half a dozen or so updates did cause some problems due, I think, to faulty code updates, sometime around the end of June, beginning of July. I have also used the EW-7811Un on all these different versions as well with just the same results so I don't think there are any problems with the driver. I did see the TKIP/CCMP issue but have never seen any other obvious major problem and certainly no obvious speed issues. I do sometimes see the transfer rates vary quite considerably but generally dependent on time of day, dependent on local internet usage, or what is happening on the network, whether it is busy or not.

On the whole I find the EW-7811Un and TL-WN725N pretty good compared with other wifi adaptors I've tried (e.g Netgear WNA1100 - Atheros ath9k driver, and Edimax EW-7622UMn - Realtek rtl8712 driver)


MrEngman
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7ewis
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 5:58 pm

MrEngman wrote:
7ewis wrote:
MrEngman wrote: You could try changing pairwise=TKIP to pairwise=CCMP
MrEngman
After a reboot, it seems to be working still after doing this. But it just seems slower than normal?

Haven't tried unplugged it yet, I'll try a shutdown now and move it somewhere else and see if it's still working.
You could always try the cut down version of wpa_supplicant.conf I suggested and see how that behaves. wpa_supplicant will then sort out the parameters it needs itself.

I think I can say I've tried every single update of raspbian, about 120 different versions using rpi-update since 3.6.11+ appeared, as I try to keep the rtl8188eu wifi driver, for the TP-LINK TL-WN725N V2, up to date and have never seen any major problems, although half a dozen or so updates did cause some problems due, I think, to faulty code updates, sometime around the end of June, beginning of July. I have also used the EW-7811Un on all these different versions as well with just the same results so I don't think there are any problems with the driver. I did see the TKIP/CCMP issue but have never seen any other obvious major problem and certainly no obvious speed issues. I do sometimes see the transfer rates vary quite considerably but generally dependent on time of day, dependent on local internet usage, or what is happening on the network, whether it is busy or not.

On the whole I find the EW-7811Un and TL-WN725N pretty good compared with other wifi adaptors I've tried (e.g Netgear WNA1100 - Atheros ath9k driver, and Edimax EW-7622UMn - Realtek rtl8712 driver)


MrEngman
Okay, thanks. I'll give it a go!

The Pi has been working for about half an hour, and then just froze up and the Wi-Fi cut off again! If I do an arp -a on my Mac, it comes up with this:

raspberrypi.lan (192.168.1.96) at (incomplete)

What does it mean when it says incomplete? I have been seeing that quite a lot when running this command after having some trouble with it.

I did read a lot of good reviews, which is why I bought it. I'm glad it's better than the others you have tried, I wish it still worked properly for me though!
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MrEngman
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Re: Edimax Wi-Fi adapter not functioning correctly

Tue Dec 24, 2013 6:35 pm

Just tried arp -a on my Pi and on a Windows laptop and it shows some other machines on the network and it appears the (incomplete) should be the MAC address. No idea why it doesn't show it unless as you say it is disconnected and if it tries getting it from the Pi using it's IP address it cannot.


MrEngman
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7ewis
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Re: Edimax Wi-Fi adapter not functioning correctly

Wed Dec 25, 2013 1:24 am

Yeah I guess it could be trying to use the IP but failing as it isn't connected anymore, but I've never seen that before!

I think I might try flashing an SD (again) and then manually setting up the Wi-Fi over SSH in the interfaces file, then rebooting and disconnecting the Ethernet cable.

I never knew how simple it was to setup, so I always booted to the GUI to setup Wi-Fi, which was annoying to have to connect to a screen anyway.

My wpa_suplicant was created by the Wi-Fi Config app on the desktop, which theoretically should work, and has previously.

I'd happily pay an extra £10 to have built in Wi-Fi instead of buying an adapter and having all these comparability issues!
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