My Ubuntu 10.10 on my laptop Lenovo T400 lost its wireless connection, and couldn't detect the available wireless networks, while being in the middle of working.
This happended before and my solution was to reboot my OS. But now I am in the middle of working, and would like to find a way without reboot. In NetworkManager applet 0.8.1, disabling and then enabling Networking does not work. So I then followed Wireless troubleshooting.
First, I ran the following command, which says my wlan0 is "Disabled":
$sudo lshw -C network *-network DISABLED description: Wireless interface product: PRO/Wireless 5100 AGN [Shiloh] Network Connection vendor: Intel Corporation physical id: 0 bus info: pci@0000:03:00.0 logical name: wlan0 version: 00 serial: 00:26:c6:3e:30:34 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=iwlagn driverversion=2.6.35-28-generic firmware=220.127.116.11 latency=0 link=no multicast=yes wireless=IEEE 802.11abg resources: irq:48 memory:f4200000-f4201fff
In such case, the link asks me to "Check that the device is on” next:
Many wireless network devices can be turned on or off. Check to see if there is a hardware switch, some devices can be switched off from Windows and may need to be turned back on from Windows.
As I did not switch from Windows, I was wondering how to check if there is a hardware switch? How can I turn my wireless network device on? Thanks!