wlan0 depends on eth0

Having installed the Edimax USB WiFi dongle, I am getting sttrange behaviour:

If my ethernet cable is plugged in, WiFi works. But if I unplug the cable, WiFi stops working and does not get alive after reboot.

I connect through USB and can find the following:

iwconfig

wlan0 IEEE 802.11bgn ESSID:“KangYatze”
Mode:Managed Frequency:2.432 GHz Access Point: 00:0C:F6:D6:6A:F0
Bit Rate=150 Mb/s Tx-Power=20 dBm
Retry long limit:7 RTS thr=2347 B Fragment thr:off
Encryption key:off
Power Management:off
Link Quality=31/70 Signal level=-79 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:1 Missed beacon:0
lo no wireless extensions.
eth0 no wireless extensions.
usb0 no wireless extensions.

ifconfig

eth0 Link encap:Ethernet HWaddr 90:59:af:4e:19:7f
inet addr:192.168.0.132 Bcast:192.168.0.255 Mask:255.255.255.0
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
Interrupt:56
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:100 errors:0 dropped:0 overruns:0 frame:0
TX packets:100 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:9128 (9.1 KB) TX bytes:9128 (9.1 KB)
usb0 Link encap:Ethernet HWaddr a2:75:01:e1:d0:93
inet addr:192.168.7.2 Bcast:192.168.7.3 Mask:255.255.255.252
inet6 addr: fe80::a075:1ff:fee1:d093/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:5212 errors:0 dropped:0 overruns:0 frame:0
TX packets:127 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:431464 (431.4 KB) TX bytes:24602 (24.6 KB)
wlan0 Link encap:Ethernet HWaddr 80:1f:02:ae:ee:ce
inet addr:192.168.0.133 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::821f:2ff:feae:eece/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:191 errors:0 dropped:0 overruns:0 frame:0
TX packets:9 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:15359 (15.3 KB) TX bytes:1054 (1.0 KB)

lsusb

Bus 001 Device 002: ID 7392:7811 Edimax Technology Co., Ltd EW-7811Un 802.11n Wireless Adapter [Realtek RTL8188CUS]
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

lsmod | grep rtl8192cu

rtl8192cu 88700 0
rtlwifi 78422 1 rtl8192cu
rtl8192c_common 60882 1 rtl8192cu
mac80211 500877 3 rtlwifi,rtl8192c_common,rtl8192cu

cat interfaces

==================================================================

The loopback network interface

auto lo
iface lo inet loopback

==================================================================

WiFi

auto wlan0
iface wlan0 inet static
address 192.168.0.133
netmask 255.255.255.0
gateway 192.168.0.1
dns-nameservers 213.46.228.196 62.179.104.196
wpa-ssid “"
wpa-psk "

(ssid and key made unreadable for this pub, however they can not be doubted as the
connection works if eth0 activated)

==================================================================

wired ethernet

auto eth0
iface eth0 inet static
address 192.168.0.132
netmask 255.255.255.0
gateway 192.168.0.1
dns-nameservers 213.46.228.196 62.179.104.196

==================================================================

Ethernet/RNDIS gadget (g_ether)

… or on host side, usbnet and random hwaddr

iface usb0 inet static
address 192.168.7.2
netmask 255.255.255.0
network 192.168.7.0
gateway 192.168.7.1

I can see nothing missing, and the blue led in the dongle is on.

Any help is highly appreciated!

I am having this same problem. Were you able to resolve it?