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Core 3 + Edimax EW-7811UN: Wifi unstable

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Core 3 + Edimax EW-7811UN: Wifi unstable

Posted: 03 Aug 2018, 09:11
by matt.s
Hello,

I'm having trouble with unstable wifi when using the Edimax EW-7811UN you're selling in the shop. It works at the beginning, but after some time I can't ping any server on the internet, not even my router that the wifi is connected to. "iwgetid" still says I'm connected to my wifi, as does the wifi icon on the upper right corner of the desktop.

I have the impression that is happens mostly when I'm using wifi to transfer data, e.g. during apt update / upgrade. When it's idle it seems to be more stable. The wifi stick becomes rather warm, maybe it's an overheating problem?

Unplugging the wifi stick and replugging it solve the problem, until it drops out during the next heavy traffic event again. Here are some dmesg outputs, where else should I look to diagnose the problem?

dmesg after wifi stops working, before replugging the wifi stick:

Code: Select all

[    5.268277] piControl: set BridgeState to running
[    8.027644] gpiomem-bcm2835 3f200000.gpiomem: Initialised: Registers at 0x3f200000
[   12.394369] rtl8192cu: Chip version 0x10
[   12.513431] logitech-djreceiver 0003:046D:C52B.0003: hiddev0,hidraw0: USB HID v1.11 Device [Logitech USB Receiver] on usb-3f980000.usb-1.3/input2
[   12.724689] rtl8192cu: Board Type 0
[   12.725552] rtl_usb: rx_max_size 15360, rx_urb_num 8, in_ep 1
[   12.726767] rtl8192cu: Loading firmware rtlwifi/rtl8192cufw_TMSC.bin
[   12.832203] ieee80211 phy0: Selected rate control algorithm 'rtl_rc'
[   12.975659] usbcore: registered new interface driver rtl8192cu
[   13.310883] input: Logitech K400 Plus as /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.3/1-1.3:1.2/0003:046D:C52B.0003/0003:046D:404D.0004/input/input0
[   13.345952] logitech-hidpp-device 0003:046D:404D.0004: input,hidraw1: USB HID v1.11 Keyboard [Logitech K400 Plus] on usb-3f980000.usb-1.3:1
[   15.909478] rtl8192cu: MAC auto ON okay!
[   15.953994] rtl8192cu: Tx queue select: 0x05
[   16.624159] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
[   16.927972] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup
[   18.002563] wlan0: authenticate with 00:a0:57:37:de:d9
[   18.039970] wlan0: send auth to 00:a0:57:37:de:d9 (try 1/3)
[   18.140480] wlan0: send auth to 00:a0:57:37:de:d9 (try 2/3)
[   18.250499] wlan0: send auth to 00:a0:57:37:de:d9 (try 3/3)
[   18.360476] wlan0: authentication with 00:a0:57:37:de:d9 timed out
[   18.558245] smsc95xx 1-1.1:1.0 eth0: link up, 100Mbps, full-duplex, lpa 0xCDE1
[   19.682723] wlan0: authenticate with 44:4e:6d:43:b5:18
[   19.709417] wlan0: send auth to 44:4e:6d:43:b5:18 (try 1/3)
[   19.737631] wlan0: authenticated
[   19.740486] wlan0: associate with 44:4e:6d:43:b5:18 (try 1/3)
[   19.805691] wlan0: deauthenticated from 44:4e:6d:43:b5:18 while associating (Reason: 9=STA_REQ_ASSOC_WITHOUT_AUTH)
[   21.143785] wlan0: authenticate with 44:4e:6d:43:b5:18
[   21.170087] wlan0: send auth to 44:4e:6d:43:b5:18 (try 1/3)
[   21.251650] wlan0: authenticated
[   21.260457] wlan0: associate with 44:4e:6d:43:b5:18 (try 1/3)
[   21.267058] wlan0: deauthenticated from 44:4e:6d:43:b5:18 while associating (Reason: 9=STA_REQ_ASSOC_WITHOUT_AUTH)
[   22.583489] wlan0: authenticate with 00:a0:57:37:de:d9
[   22.609894] wlan0: send auth to 00:a0:57:37:de:d9 (try 1/3)
[   22.710431] wlan0: send auth to 00:a0:57:37:de:d9 (try 2/3)
[   22.820474] wlan0: send auth to 00:a0:57:37:de:d9 (try 3/3)
[   22.930443] wlan0: authentication with 00:a0:57:37:de:d9 timed out
[   24.673117] wlan0: authenticate with 44:4e:6d:43:b5:18
[   24.701269] wlan0: send auth to 44:4e:6d:43:b5:18 (try 1/3)
[   24.724596] wlan0: authenticated
[   24.730505] wlan0: associate with 44:4e:6d:43:b5:18 (try 1/3)
[   24.840439] wlan0: associate with 44:4e:6d:43:b5:18 (try 2/3)
[   24.950424] wlan0: associate with 44:4e:6d:43:b5:18 (try 3/3)
[   25.060442] wlan0: association with 44:4e:6d:43:b5:18 timed out
[   27.282519] wlan0: authenticate with 44:4e:6d:43:b5:18
[   27.309733] wlan0: send auth to 44:4e:6d:43:b5:18 (try 1/3)
[   27.333159] wlan0: authenticated
[   27.340544] wlan0: associate with 44:4e:6d:43:b5:18 (try 1/3)
[   27.367125] wlan0: RX AssocResp from 44:4e:6d:43:b5:18 (capab=0x431 status=0 aid=1)
[   27.373477] wlan0: associated
[   27.531498] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
[  769.063427] fuse init (API version 7.26)
dmesg after replugging the wifi stick, wifi working again:

Code: Select all

[   27.531498] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
[  769.063427] fuse init (API version 7.26)
[ 1398.014920] usb 1-1.2: USB disconnect, device number 4
[ 1398.048119] wlan0: deauthenticating from 44:4e:6d:43:b5:18 by local choice (Reason: 3=DEAUTH_LEAVING)
[ 1398.188206] rtl_usb: reg 0x102, usbctrl_vendorreq TimeOut! status:0xffffffed value=0x90e1317
[ 1398.188223] rtl_usb: reg 0x422, usbctrl_vendorreq TimeOut! status:0xffffffed value=0xf00069ce
[ 1398.188239] rtl_usb: reg 0x542, usbctrl_vendorreq TimeOut! status:0xffffffed value=0x1070454
[ 1398.188266] rtl_usb: reg 0x1cc, usbctrl_vendorreq TimeOut! status:0xffffffed value=0x5011c
[ 1416.738167] usb 1-1.2: new high-speed USB device number 6 using dwc_otg
[ 1416.869705] usb 1-1.2: New USB device found, idVendor=7392, idProduct=7811
[ 1416.869715] usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 1416.869720] usb 1-1.2: Product: 802.11n WLAN Adapter
[ 1416.869726] usb 1-1.2: Manufacturer: Realtek
[ 1416.869731] usb 1-1.2: SerialNumber: 00e04c000001
[ 1416.870731] rtl8192cu: Chip version 0x10
[ 1417.003565] rtl8192cu: Board Type 0
[ 1417.003868] rtl_usb: rx_max_size 15360, rx_urb_num 8, in_ep 1
[ 1417.003957] rtl8192cu: Loading firmware rtlwifi/rtl8192cufw_TMSC.bin
[ 1417.004547] ieee80211 phy1: Selected rate control algorithm 'rtl_rc'
[ 1417.230145] rtl8192cu: MAC auto ON okay!
[ 1417.281277] rtl8192cu: Tx queue select: 0x05
[ 1418.091217] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
[ 1419.440034] wlan0: authenticate with 44:4e:6d:43:b5:18
[ 1419.469454] wlan0: send auth to 44:4e:6d:43:b5:18 (try 1/3)
[ 1419.578200] wlan0: send auth to 44:4e:6d:43:b5:18 (try 2/3)
[ 1419.688184] wlan0: send auth to 44:4e:6d:43:b5:18 (try 3/3)
[ 1419.695302] wlan0: authenticated
[ 1419.698233] wlan0: associate with 44:4e:6d:43:b5:18 (try 1/3)
[ 1419.801583] wlan0: RX AssocResp from 44:4e:6d:43:b5:18 (capab=0x431 status=0 aid=1)
[ 1419.808293] wlan0: associated
[ 1419.949438] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
Btw, none of the other computers on the same network is experiencing this problem so.

Re: Core 3 + Edimax EW-7811UN: Wifi unstable

Posted: 03 Aug 2018, 13:40
by dirk
Hello matt.s,
I'm sorry to hear that you have problems with the USB-WLAN stick from our shop.
We ourselves often use this stick here, e.g. for trade fair exhibits and
also internally. So far we have not had such experiences.

Certainly the heat is a possible cause of the problem.
At the moment we have a heat of over 30 °C here in the office...
It is then quite easy to add another 10°C in the case.

Please try to use the stick with an USB extension.
It may also help to cool the stick e.g. with a ventilator.

Please check it again with a system update or similar download conditions.
If the problem then no longer exists, the cause is actually
the temperature.

Alternatively, you can exchange the stick for one with an external antenna.

Re: Core 3 + Edimax EW-7811UN: Wifi unstable

Posted: 22 Oct 2018, 13:59
by ChristianLehmann
Hello,

we have the same problem here (with RevPi Core 3 and WiFi-Stick from the shop) -- in regular intervals the stick terminates the connection. After some minutes it is possible reconnect again, but for our application this behaviour is not suitable. Can you recommend another adapter which works more reliable with the RevPi (we want to avoid the use of an additional router )?

Best regards
Christian
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