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I updated Ubuntu 14.04 system when it asked for a software update and after the installation I observed that no WiFi network is detected.

I rechecked the driver setting and it is set to Broadcom driver in Additional driver tab of Software and updates.

It is not a problem with Wifi hardware as it works well in Windows. I have copied the update history here.

I am not sure which package is causing the problem and ways to crack the problem.

Appreciate your help to identify and tackle the problem.

Hardware details

  • Laptop : Dell Vostro 2520
  • WiFi chip : BCM43142

Output of uname -a

Linux ilabs 3.13.0-49-generic #81-Ubuntu SMP Tue Mar 24 19:29:48 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

Below is output of sudo lshw -C network

     *-network UNCLAIMED     
       description: Network controller
       product: BCM43142 802.11b/g/n
       vendor: Broadcom Corporation
       physical id: 0
       bus info: pci@0000:07:00.0
       version: 01
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list
       configuration: latency=0
       resources: memory:f7c00000-f7c07fff
  *-network
       description: Ethernet interface
       product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0
       bus info: pci@0000:09:00.0
       logical name: eth0
       version: 07
       serial: e0:db:55:b2:71:45
       size: 100Mbit/s
       capacity: 1Gbit/s
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=rtl8168e-3_0.0.4 03/27/12 ip=192.168.1.100 latency=0 link=yes multicast=yes port=MII speed=100Mbit/s
       resources: irq:41 ioport:e000(size=256) memory:f0004000-f0004fff memory:f0000000-f0003fff

Output of rfkill list

0: hci0: Bluetooth
    Soft blocked: no
    Hard blocked: no

Output of sudo dkms status

bcmwl, 6.30.223.248+bdcom, 3.13.0-49-generic, x86_64: installed
4
  • You can find General drivers and instructions [here]( linuxwireless.org/welcome). The Broadcom driver is proprietary and a previous update to Ubuntu Studio broke my installation. Having gone through manual installation several times before [not related to Ubuntu breaking] I pulled the Broadcom card and plugged the ethernet into a spare router running DD-WRT for my wireless. Now my wireless is decoupled from my OS and stays configured. Apr 10, 2015 at 3:59
  • Unfortunately, a dell-vostro label isn't specific enough and we don't have your hardware to debug the issue, so please provide more hardware information and edit your question to include that information. See "Identifying the exact hardware" in this Q&A on how and what is useful to provide. And while you're at it, please also include the output of dkms status.
    – gertvdijk
    Apr 10, 2015 at 16:11
  • Try going back to older kernel. Select one during boot in Advanced Options for Ubuntu Apr 10, 2015 at 17:36
  • use the green check mark next to an answer or create your own answer, don't use "solved" in the title.
    – Mateo
    Apr 11, 2015 at 17:09

4 Answers 4

1

Finally, I figured out the problem.It was with the version of the GCC.I have two version of GCC, gcc-4.4(which I need for some CAD tools) and gcc-4.8. Unfortunately it was set to gcc-4.4 at the time of update.So I guess the driver is compiled using gcc-4.4 which was failed to load.

To resolve this,I did

  1. Switch gcc to gcc-4.8
  2. In Additional driver tab of Software and updates,select Do not use the device and apply changes.
  3. Then again switch back to the additional driver(Broadcom driver in my case) shown in Additional driver tab and apply changes.
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I had a similar problem starting from the 10th as well (though admittedly I do not have a Broadcom card), and it seems like Network Manager was the culprit. I haven't found a straightforward fix, but I was able to boot from a live CD, mount the hard drive, apt-get remove network-manager, and apt-get install wicd. Wicd seems to have some problems coming up on startup, but if I start in manually, it finds and connects to my wireless just fine.

Here's the step-by-step instructions, for anyone with similar issues who either is also having problems with their ethernet (which was also an issue on my computer): Reboot and load the live CD. Go to "Try Ubuntu" Open a terminal, and type:

sudo su -
mount /dev/sda1 /mnt
mount --bind /proc /mnt/proc
mount --bind /dev /mnt/dev
mount --bind /sys /mnt/sys
chroot /mnt
apt-get remove network-manager
apt-get install wicd

From here, you can do any other package (un)installations. Then,

umount /mnt{/proc,/dev,/sys,}
umount /mnt

And reboot.

For reference, I am using an Intel wireless interface. Rebooting from different kernels did not solve the problem, but booting from the Live CD was fine, as was working from Debian or Gentoo.

0

The first thing you want to do when, after an update, some hardware doesn't work, is to reboot to the previous kernel, which is kept. You can find them in the boot menu. This kind of thing can happen from time to time with proprietary drivers and is one of the main reasons they are so intensely hated by many. Very often, though, you can "fix" it by simply booting the previous kernel for a while until the problem is fixed with another update. If you're able, you should file a bug on Launchpad.net, providing as much details as possible about your system and hardware.

-1

you can restart the network-manager service using the command

/etc/init.d/network-manager restart

or try restarting the network service as well.

/etc/init.d/network restart

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