Comment 383 for bug 621265

I thought I'd share my experience with this bug. When I upgraded to Ubuntu 11.10 I discovered I had a slow wireless connection, and after a bit of searching around found this page. The disable_hw_scan=0 fix in #370 seemed to fix my problem, but like others I was getting loads of "Microcode SW error detected" errors.

But after applying the fix I started to have problems with Ubuntu freezing occasionally. Everything would just stop working, and I'd have to do a hard reset by holding down my laptop's power button. This happened several times over a week or two, and I'd had enough when it happened twice in one day. So I decided to remove the /etc/modprobe.d/iwl3945.conf file I'd created to undo the fix. And afterwards the crashes stopped, though obviously I was left with slow wi-fi. But I decided to live with it and gave up looking for a fix, hoping a future update would fix things.

Last night though I got impatient and started looking again. Long story short, I decided to try using Wicd instead of NetworkManager. And since then things seem to be working fine, my wireless speeds are back to normal, perhaps even slightly better than when I had the disable_hw_scan=0 fix applied. Just to reiterate, I removed the fix before installing Wicd and don't have it applied now, so the bug appears to be with NetworkManager, or at least in my case it does. Perhaps other people who have had this issue since upgrading to 11.10 (and I had never had a wireless issue since I started using Ubuntu 3+ years ago) could try using Wicd and see if it fixes things for them too.

Here's my system specs:
lspci -vnn |grep -A3 Wireless
0c:00.0 Network controller [0280]: Intel Corporation PRO/Wireless 3945ABG [Golan] Network Connection [8086:4222] (rev 02)
 Subsystem: Intel Corporation Device [8086:1021]
 Flags: bus master, fast devsel, latency 0, IRQ 45
 Memory at f9fff000 (32-bit, non-prefetchable) [size=4K]

uname -a
Linux cdowning-laptop 3.0.0-13-generic #22-Ubuntu SMP Wed Nov 2 13:27:26 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux

lsb_release -rd
Description: Ubuntu 11.10
Release: 11.10