Nothing drives me madder than anything than WiFi troubles except maybe outboard motor troubles..
Sometimes it's a simple oversight so I'm embarrassed to mention the number of times I have inadvertently whacks the <FN> key and the <F3> key (with the nearly invisible blue print indicating wifi). This is a 'hardware' switch that toggles power to the radio. Some models had a real mechanical switch, others, like mine and possibly this yours, the hardware switch is a couple of key strokes.
I go to send the mail,e.g., and not only had I lost my connection, but all the Access Points broadcasting their SSID tags are gone. I chase my tail for a few minutes stumbling to the discovery that I don't have a wi-fi card at all. This is news to me because I just used it.<doink>Oh yeah...I've got this bloody switch that I accidentally keep flipping.
To make matters worse the Wifi "ON" idiot light was either off or on, but didn't seem to reflect if the wifi was working. because there is also a 'software' switch that disconnects it from talking the kernel, but maintaining power to the radio. The light is on, but there is nobody home.
That was me until I learned to check if there was gas in the tank, or the fuel cutoff valve was turned the right way before I pulled the starter cord for five minutes panting a curse to some hapless horse and the fella who just rode it.
I was saved from madness by
rfkill list allCode:
wadda@mini:~$ rfkill list all
0: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no
wadda@mini:~$ rfkill block wifi
Can't open RFKILL control device: Permission denied
wadda@mini:~$ sudo !!
sudo rfkill block wifi
[sudo] password for wadda:
wadda@mini:~$ rfkill list all
0: phy0: Wireless LAN
Soft blocked: yes
Hard blocked: no
wadda@mini:~$ sudo rfkill unblock wifi
wadda@mini:~$ rfkill list all
0: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no
wadda@mini:~$
I could see if my WIFI was blocked either soft or hard and then 'flick' the right switch using
sudo to get permission.
There are a set of options behind
rfkill --help or a bit more words in
man rfkillQuote:
unblock index|type
Enable the device corresponding to the given index. If the
device is hard-blocked, e.g. via a hardware switch, it will
remain unavailable though it is now soft-unblocked.
This way you avoid chasing your tail. I've heard it does happen.
But I can tell we are not that lucky and it is not that the wifi card is switched 'off' that it is not recognized, but that it was ignored completely. Machines can be very rude.
lspci | grep lan -i will tell what it thinks is there.
Code:
wadda@mini:~$ lspci |grep lan -i
03:00.0 Network controller: Realtek Semiconductor Co., Ltd. RTL8191SEvB Wireless LAN Controller (rev 10)
LiSt PCI devices p|pe it to Globally search a Regular Expression and Print "lan' -It doesn't matter if it's uppercase/lowercase.
It the Wifi 'card' is connected through USB then it will be
lsusb | grep lan -i. Surprise-surprise some machines have the WiFi on the USB bus but still internal.
Then we'll check which modules are being called up to see it the automagic detection is stuffed up.
lsmod | grep wifi or
grep 802 as one might miss what another returns.
Code:
wadda@mini:~$ lsmod | grep wifi
rtlwifi 79673 1 rtl8192se
mac80211 606457 2 rtlwifi,rtl8192se
cfg80211 510937 2 mac80211,rtlwifi
If the number seem to match, but it still doesn't work I pick something identifiable
dmesg | grep rtl -i to look through Displayed MESsaGes pipe it to grep searching for a scrap.
Code:
wadda@mini:~$ dmesg | grep rtl -i
[ 27.647762] rtl8192se: FW Power Save off (module option)
[ 27.647786] rtl8192se: Driver for Realtek RTL8192SE/RTL8191SE
[ 27.647786] Loading firmware rtlwifi/rtl8192sefw.bin
[ 27.818970] ieee80211 phy0: Selected rate control algorithm 'rtl_rc'
If it looks fine, but still doesn't work, I check to see if anyone else in the world has this problem, or it just me. I was told the rtl8192se drives the RTL8191SEvB device.