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Old 5th July 2009, 03:46 PM
Reworker7 Offline
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WLAN frequently disconnects with kernel: iwlagn: Microcode SW error detected

I've been using Fedora on the same notebook (HP8710w) since the release of Fedora 9 without any issues. However, now my WLAN frequently disconnects with the message:

kernel: iwlagn: Microcode SW error detected. Restarting 0x2000000. I'm using the kernel. I experienced no problems under Fedora 9 or 10 with the WLAN - it was very reliable. My WLAN adapter is the Intel 4965AGN, which I use in conjunction with an Edimax router.


wlan0 Link encap:Ethernet HWaddr 00:21:5C:2F:1A:E5
inet addr: Bcast: Mask:
inet6 addr: fe80::221:5cff:fe2f:1ae5/64 Scope:Link
RX packets:3900921 errors:0 dropped:0 overruns:0 frame:0
TX packets:3159053 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:3857657556 (3.5 GiB) TX bytes:739452534 (705.1 MiB)


wlan0 IEEE 802.11abgn ESSID:"XXXXX"
Mode:Managed Frequency:2.447 GHz Access Point: 00:1F:1F:1D:04:70
Bit Rate=60 Mb/s Tx-Power=15 dBm
Retry min limit:7 RTS thr:off Fragment thr=2352 B
Power Management:off
Link Quality=100/100 Signal level:-38 dBm Noise level=-90 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0

Any suggestions for what might be the problem here? Sometimes I can get three or four disconnects in one hour, other times it might be fine for an entire afternoon. There does not appear to be a "trigger" mechanism. Thanks in advance for any help or suggestions.
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Old 20th July 2009, 05:03 AM
tkalfaoglu Offline
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Join Date: Oct 2007
Posts: 352
I have been suffering from the same thing since Fedora 11 upgrade.
I found that rmmod iwlagn && modprobe iwlagn cures it.
However, this also has a "feature" of completely crashing the machine every forth time.
It only happens at full blast - that is, if I copy something > 50 MB from another PC on the LAN..

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Old 13th August 2009, 07:10 PM
dca Offline
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I, too, am getting this... Can anyone verify if it has something to do with associating an AP by clicking on 'Edit Connections' and manually adding a wireless network and all info or does the problem happen when clicking on avail AP and then inputting connection info or it doesn't matter, either way causes same result...
Linux Registered User# 419773
"It Is What It Is"
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Old 23rd August 2009, 01:48 PM
malikons Offline
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Join Date: Aug 2009
Posts: 6
same problem

I am seeing exactly the same issue but couldn't figure out the problem from googling. I am running F11 on HP6910p for over a month and was stable. All of a sudden, my wlan started acting up and I have no clue what caused it. I sorta hate these long list of updates every other day but I believe they are somewhat important but they tend to mess up your otherwise fine working OS.

Anyway, coming from Red Hat Enterprise world, I don't think I'll stick to this flaky OS for a long time. I must admit, it works perfectly for everything else but the wireless part. Here is the error message is see:

iwlagn: Microcode SW error detected. Restarting 0x82000000

Not just this, I do now see a lot of other errors too, such as:

wpa_supplicant[1907]: segfault at 900004f ip 0807f9fa sp bf994780 error 4 in wpa_supplicant[8048000+61000]

mac80211-phy0: failed to remove key (0, 00:24:fe:00:b2:96) from hardware (-22)

I have tried almost everything I found on Internet to fix this but nothing worked. One guy has a suggestion to decrease the power of Wifi since he thinks it might be related to over heating of Wireless NIC and that worked for him but not me. The other recommended using rawhide kernel but others trying to do the same screwed their OS, so I won't follow those instructions. My laptop is little more than a fun laptop and it is critical for me to stay up and running with no connectivity issues.

Hope Fedora will come up with a solution sooner than later. If anyone else has a solution, please post here.

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Old 31st August 2009, 11:42 AM
tkalfaoglu Offline
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Posts: 352
No solution still? The issue is still going on..
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Old 1st September 2009, 10:21 PM
tkalfaoglu Offline
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Posts: 352
This problem seems to be from the temperature of the wifi chip..
You can see the temperature by using:
# cat /sys/bus/pci/drivers/iwlagn/0000\:06\:00.0/temperature

if there is heavy usage, the temp goes up. Over 60, my wifi gets a SW error.
To keep it cool, two things seem to work:

# iwconfig wlan0 power on
# echo 8 > /sys/bus/pci/drivers/iwlagn/0000\:06\:00.0/power_level

Try and see if these help. Note that these are contradictory: power on allows the system to change the card's output level,
and echo 8 > .. command actually sets the power output to its lowest setting. So, do the iwconfig thing first, if it still hangs,
turn off power management with iwconfig wlan0 power off, then try the second command (the echo).

I just downloaded a 700MB file using this, and I kept a close eye on the temperature.. It went up to 59 and then came down. Also try lifting up the laptop to give it more air..

PS: At any time you can see the power level using:
cat /sys/bus/pci/drivers/iwlagn/0000\:06\:00.0/power_level

The highest (hottest) index value is 0, lowest seems to be 8.


Last edited by tkalfaoglu; 1st September 2009 at 10:30 PM.
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Old 1st September 2009, 10:36 PM
tkalfaoglu Offline
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Join Date: Oct 2007
Posts: 352
I just downloaded several more large files -- no crashes
I just set it to
iwconfig wlan0 power on

and I believe it set its power output to 3, instead of its default 0 (max power).

PS: I also have:

# more /etc/modprobe.d/local.conf
options iwlagn swcrypto50=1

I dont know if that helps or not.


Last edited by tkalfaoglu; 2nd September 2009 at 05:51 AM.
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Old 2nd September 2009, 05:50 AM
tkalfaoglu Offline
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Join Date: Oct 2007
Posts: 352
it also seems that if I use gnome to do the download, I crash more often!
If I use command line FTP, it seems more resilient..
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Old 2nd September 2009, 01:05 PM
malikons Offline
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Join Date: Aug 2009
Posts: 6
Transmission is the cause?

With me, it only happens as soon as I fire up Transmission and start downloading some torrent. Is this some crazy anti-piracy tactic from Fedora

I've tried downloading other files using different protocols with the rate up to 1MB/s but my wireless remained connected. Any clue what Transmission might be doing? I'll try some other torrent app and see if I continue to experience the same.

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Old 2nd September 2009, 01:34 PM
malikons Offline
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Posts: 6
Thanks for the other suggestions of changing the power_level and keeping an eye on temperature. my /sys/bus/pci/drivers/iwlagn/0000\:10\:00.0/temperature give the reading of 341. Any clue how to convert it to a more understandable metric?

I use docking station so my laptop is always lifted from the ground. I never use it on my lap so it

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Old 19th December 2009, 04:26 PM
Szpak Offline
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Join Date: Mar 2004
Location: Poland
Posts: 106
You could also check a workaround from bugzilla:

it seems to work as well.

Note, a file has to named options.conf (instead of options) to not be ignored.

timeoff.wsisiz.edu.pl/rpms.html - Various RPM packages for Fedora Core
solidsoft.wordpress.com - Solid Soft - Working code is not enough
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