Comment 27 for bug 981167

I'm also experiencing this problem - but I'd say I have it for a week - everything worked fine until last week (I've switched to precise during the beta phase).

executing
ifconfig wlan0 down; ifconfig wlan0 up; route add default gw 192.168.1.1

seems to re-enable wifi for a while, but I can never tell for how long. sometimes it works an hour, sometimes it works only a minute.

my wifi card is

           *-network
                description: Wireless interface
                product: Ultimate N WiFi Link 5300
                vendor: Intel Corporation
                physical id: 0
                bus info: pci@0000:05:00.0
                logical name: wlan0
                version: 00
                serial: xx:xx:xx:xx:xx:xx
                width: 64 bits
                clock: 33MHz
                capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
                configuration: broadcast=yes driver=iwlwifi driverversion=3.2.0-29-generic firmware=8.83.5.1 build 33692 ip=192.168.1.7 latency=0 link=yes multicast=yes wireless=IEEE 802.11abgn
                resources: irq:49 memory:f0a00000-f0a01fff

$ uname -a
Linux juergen 3.2.0-29-generic #46-Ubuntu SMP Fri Jul 27 17:03:23 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux