Ubuntu – BCM 4313 proprietary driver blocks WiFi for other devices

broadcomdriverswireless

I run a home wlan and a few days ago I upgraded a hp dv7 pavilion laptop from Oneiric to Precise. I had the proprietary Broadcom STA driver (wl module) activated.

Whenever this laptop was connected to WiFi had speedtest.net result of 8 Mbps (down) and all other machines (laptops, smartphones) could only get speedtest.net results well below 1 Mbps (mostly 500 Kbps) with severe ping problems and other bizarre effects. When the laptop was off everything was OK for the other machines.

Thinking about this a little I decided to remove the STA proprietary driver and use the opensource one. Everything works perfectly now for all the machines on the Wifi.

I wonder if the STA driver update in precise is rotten since it appears that it transformed my machine into a WiFi jammer. Is this possible ?

It seems that this issue is lined to the BCM 4314 itself, not a particular laptop.

What may be the possible reason for such a peculiar behavior? Can I overcome it without disabling the proprietary driver? What can I do to troubleshoot this problem?

Best Answer

My guess:

It's not a definitive answer, but my best guess is poor broadcast power control on the closed source blob resulting in other well managed cards (hosts or AP) turning down their sensitivity so they don't get blown by the power.

If I'm right:

It sounds like a non-fixable problem since it's in the blob unless you script a bunch of power control.

How could it theoretically be tested:

If you have three test boxes, I'ld test it like this

1) Install some tool that lets you see a packet's network's relative power.

I'm sure there's a CLI util to do it at a whack, but kismet is already installed on my laptops and gives me enough information.

2) With the broadcom box OFF, check the power of your box number 3 in kismet.

3) Next turn it off and place the broadcom box in the same location.

4) Check in kismet again. If my guess is right, the broadcom box should show significantly more signal strength.

Related Solutions

Ubuntu – Dell Upgrade to 13.04 & 13.10 No wifi, graphic card driver and bluetooth Problem

Wifi/Graphic Driver Fix

In the end i found the problem was fixed by seeing the post Dell Inspiron 1525, Upgraded to 12.04 and have lost Wireless Internet Connection

I used the commands:

sudo apt-get remove bcmwl-kernel-source
sudo apt-get install bcmwl-kernel-source

Or use purge instead of remove to wipe it, then re-install.

This worked to re-install the wifi drivers now my wifi is working.

I wondered if maybe this would also work for the graphics driver for my ATI/AMD cards. So I tried to re-install the graphics drivers and this also worked.

The commands for the graphics fix were:

sudo apt-get remove fglrx
sudo apt-get install fglrx

Or use purge instead of remove to wipe it, then re-install.

And a big thanks to fossfreedom For solving the Bluetooth matter.

GUI window showing activated Broadcom proprietary wireless driver

As you can see, now all seems to be working.

Ubuntu – How to get proprietary Broadcom drivers to work after installation

It seems that there is some problem occurred when you installed Wireless Broadcom 802.11 driver. You can give a try to followings:

Open a terminal and execute following commands:
```
$ sudo (jockey-gtk &)
$ sudo update-grub
$ sudo update-initramfs -u
```
jockey-gtk will automatically searches all available drivers and try to fix it. Then restart your system.

Try to reconfigure installed Broadcom Wireless Driver

$ sudo dpkg-reconfigure bcmwl-kernel-source

if it still doesn't work then re-install it by completely removing it:

$ sudo apt-get autoremove bcmwl-kernel-source
$ sudo apt-get --purge remove bcmwl-kernel-source
$ sudo apt-get install bcmwl-kernel-source

Try to update your system, sometimes updating fixes a lot of issues. Update your system after removing any broken packages, residual unused packages, execute these commands:
```
$ sudo apt-get autoremove
$ sudo apt-get autoclean
$ sudo apt-get install
$ sudo apt-get update
$ sudo apt-get upgrade
```

I hope any of these steps work for you. Reply if something goes wrong..