Bug 1205 - Data transfer drops off with signal but doesn't when sigincreasenal returns
: Data transfer drops off with signal but doesn't when sigincreasenal returns
Status: VERIFIED WONTFIX
: IPW3945
Data Transfer
: 1.1.0
: Dell Debian
: P2 normal
Assigned To:
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Reported: 2007-02-09 11:18 by
Modified: 2008-12-08 22:13 (History)


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Description From 2007-02-09 11:18:50
Hi,

I've a strange problem here.  I've a Dell Inspiron 6400 laptop with an intel
3945abg built in.  I'm using Ubuntu 6.10 (Edgy) and the driver is included with
this distribution (Version 1.1.0) ieee80211 version is 1.1.13.

If I transfer data across the wireless link I get about 3Mbytes/s which I'm
happy with.  If I move with the laptop to an area with poor signal the data rate
drops off which I expect.  Once the data rate hits about 100Kbytes/s once I move
back into good signal the rate never increases above 150Kb/s  If I down the
interface and bring it up again the transfer rate increases.

I've tried this with a netgear and linksys AP's and it is the same.  I've also
used a 'live cd' of Ubuntu and configured it for the AP, same result.  I've
configured the AP's with WPA and no encryption, using wpa_supplicant with WPA
and manually configuring the interface with iwconfig for the no encryption
connection.

I've also used an old 802.11b AP that I had lying round and it worked flawlessly
on this (allbeit at 11Mb)

I've installed the latest version of the drivere (1.2.0) with the latest
ieee80211 and the problem remains.

I've been unable to insert the module with the debug setting as I keep getting
module symbol errors.  Nothing shows in dmesg or other logs.

Any Ideas?

If you can let me know how I can get more debug info on this I'd appreciate that
too.

Thanks
------- Comment #1 From 2007-04-05 00:49:55 -------
Same bug here on my Dell Inspiron 9400

modinfo ipw3945
filename:      
/lib/modules/2.6.20-13-generic/kernel/ubuntu/wireless/ipw3945/ipw3945.ko
license:        GPL
version:        1.2.0mp

0c:00.0 Network controller: Intel Corporation PRO/Wireless 3945ABG Network
Connection (rev 02)
        Subsystem: Intel Corporation Unknown device 1021
        Flags: bus master, fast devsel, latency 0, IRQ 17
        Memory at ecfff000 (32-bit, non-prefetchable) [size=4K]
        Capabilities: [c8] Power Management version 2
        Capabilities: [d0] Message Signalled Interrupts: Mask- 64bit+ Queue=0/0
Enable-
        Capabilities: [e0] Express Legacy Endpoint IRQ 0

eth1      IEEE 802.11g  ESSID:"OpenWrt"  
          Mode:Managed  Frequency:2.427 GHz  Access Point: 00:16:xx:19:xx:A2   
          Bit Rate=11 Mb/s   Tx-Power:15 dBm   
          Retry limit:15   RTS thr:off   Fragment thr:off
          Power Management:off
          Link Quality=71/100  Signal level=-64 dBm  Noise level=-65 dBm
          Rx invalid nwid:0  Rx invalid crypt:14  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:18412   Missed beacon:0


 KB/s in  KB/s out   KB/s in  KB/s out
    0.00      0.00    113.11      3.57
    0.00      0.00    111.70      4.30
    0.00      0.00    113.11      3.57
    0.00      0.00    113.19      3.59
    0.00      0.00    111.69      3.64
    0.00      0.00    111.62      3.57
    0.00      0.00    114.60      3.75
    0.00      0.00    111.62      3.73
    0.00      0.00    113.11      3.83
    0.00      0.00    110.21      3.50
    0.00      0.00    114.66      3.89
    0.00      0.00    110.24      3.57
    0.00      0.00    111.83      3.67
    0.00      0.00    111.93      3.68

eth1      Protokoll:Ethernet  Hardware Adresse 00:19:D2:B0:08:83  
          inet Adresse:192.168.1.34  Bcast:192.168.1.255  Maske:255.255.255.0
          inet6 Adresse: fe80::219:d2ff:feb0:883/64 Gültigkeitsbereich:Verbindung
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:133322 errors:15 dropped:18483 overruns:0 frame:0
          TX packets:102092 errors:0 dropped:0 overruns:0 carrier:0
          Kollisionen:0 Sendewarteschlangenlänge:1000 
          RX bytes:177937052 (169.6 MiB)  TX bytes:10423688 (9.9 MiB)
          Interrupt:17 Basisadresse:0x2000 Speicher:ecfff000-ecffffff 
------- Comment #2 From 2007-04-05 04:15:11 -------
I think 
sudo iwpriv eth1 set_mode 4
fixes the problem

------- Comment #3 From 2007-04-05 13:02:12 -------
Can you confirm that fixed it for you?

It doesn't for me.  What is that setting supposed to do?

Thanks

Chris(In reply to comment #2)
> I think 
> sudo iwpriv eth1 set_mode 4
> fixes the problem
> 
> 

------- Comment #4 From 2007-04-19 19:50:55 -------
Yes, I can reproduce this issue on SONY too. I will attach dmesg soon.
------- Comment #5 From 2007-05-25 08:51:56 -------
(In reply to comment #2)
> I think 
> sudo iwpriv eth1 set_mode 4
> fixes the problem

I also experienced this bandwidth drop-off to 150KB/s and it's been mystifying 
me for a while. I confirm that I can reproduce this problem on a Panasonic R5 
(model CF-R5KW4AXR, also with Intel 3945 built in) and also that running this 
iwpriv command seems to fix it temporarily.

It definitely seems like a bug however that the mode needs to be forced with 
iwpriv after every low-signal moment.

I can attach dmesg output etc. if required.
------- Comment #6 From 2007-06-10 09:15:15 -------
I can confirm this:

laptop: acer aspire 9411 AWSMi
distro: ubuntu feisty
kernel 2.6.20-16-generic

 modinfo ipw3945
filename: /lib/modules/2.6.20-16-generic/kernel/ubuntu/wireless/ipw3945/ipw3945.ko
license: GPL
author: Copyright(c) 2003-2006 Intel Corporation
version: 1.2.0mp
description: Intel(R) PRO/Wireless 3945 Network Connection driver for Linux
srcversion: 9B03103B15A8FE1824967C2
alias: pci:v00008086d00004227sv*sd*bc*sc*i*
alias: pci:v00008086d00004222sv*sd*bc*sc*i*
depends: ieee80211
vermagic: 2.6.20-16-generic SMP mod_unload 586
parm: antenna:select antenna (1=Main, 2=Aux, default 0 [both]) (int)
parm: disable:manually disable the radio (default 0 [radio on]) (int)
parm: associate:auto associate when scanning (default 0 off) (int)
parm: auto_create:auto create adhoc network (default 1 on) (int)
parm: led:enable led control (default 1 on)
 (int)
parm: channel:channel to limit associate to (default 0 [ANY]) (int)
parm: rtap_iface:create the rtap interface (1 - create, default 0) (int)
parm: mode:network mode (0=BSS,1=IBSS,2=Monitor) (int)


iwpriv eth1 set_mode 4 
fixes the issue
------- Comment #7 From 2007-09-04 01:45:45 -------

Hello, i can confirm this too.

laptop:
- new DELL Inspiron 6400
- Intel PRO/Wireless 3945
- Intel Pentium Dual-Core CPU
- distro: ubuntu Feisty
- kernel 2.6.20-16-generic

windows: wlan working.

i don't think that the wlan-router (Vigor2500) because with other notebooks
(intel wlan too, feisty too) i can connect without any problems.

ethernet is fully working.

reinstalling feisty did'n work. also live CD - same issue.

connecting with network-manager really a problem. also without WEP. Always i can
see the aviable wireless networks (also mine) in the network-manager-applet
(with great signal) but only in 1 of 12 cases i can connect. and then the
connection is very very slow.

I tried manual configuration, without natwork-manager and with static IPs. Since
then connecting is now Problem. But the connection is very very slow, too.

iwconfig eth1:
eth1 IEEE 802.11b ESSID:"Vigor2500"
          Mode:Managed Frequency:2.437 GHz Access Point: 00:90:4B:1A:6E:CC
          Bit Rate:11 Mb/s Tx-Power:15 dBm
          Retry limit:15 RTS thr:off Fragment thr:off
          Power Management:off
          Link Quality=66/100 Signal level=-68 dBm Noise level=-68 dBm
          Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
          Tx excessive retries:0 Invalid misc:3051 Missed beacon:0

ipw3945:
filename: /lib/modules/2.6.20-16-generic/kernel/ubuntu/wireless/ipw3945/ipw3945.ko
license: GPL
author: Copyright(c) 2003-2006 Intel Corporation
version: 1.2.0mp
description: Intel(R) PRO/Wireless 3945 Network Connection driver for Linux
srcversion: 9B03103B15A8FE1824967C2
alias: pci:v00008086d00004227sv*sd*bc*sc*i*
alias: pci:v00008086d00004222sv*sd*bc*sc*i*
depends: ieee80211
vermagic: 2.6.20-16-generic SMP mod_unload 586
parm: antenna:select antenna (1=Main, 2=Aux, default 0 [both]) (int)
parm: disable:manually disable the radio (default 0 [radio on]) (int)
parm: associate:auto associate when scanning (default 0 off) (int)
parm: auto_create:auto create adhoc network (default 1 on) (int)
parm: led:enable led control (default 1 on)
 (int)
parm: channel:channel to limit associate to (default 0 [ANY]) (int)
parm: rtap_iface:create the rtap interface (1 - create, default 0) (int)
parm: mode:network mode (0=BSS,1=IBSS,2=Monitor) (int)

"sudo iwpriv eth1 set_mode 4" does not work or change anysthing.

hoping for some help.

regards,
max
(In reply to comment #6)
> I can confirm this:
> 
> laptop: acer aspire 9411 AWSMi
> distro: ubuntu feisty
> kernel 2.6.20-16-generic
> 
>  modinfo ipw3945
> filename: /lib/modules/2.6.20-16-generic/kernel/ubuntu/wireless/ipw3945/ipw3945.ko
> license: GPL
> author: Copyright(c) 2003-2006 Intel Corporation
> version: 1.2.0mp
> description: Intel(R) PRO/Wireless 3945 Network Connection driver for Linux
> srcversion: 9B03103B15A8FE1824967C2
> alias: pci:v00008086d00004227sv*sd*bc*sc*i*
> alias: pci:v00008086d00004222sv*sd*bc*sc*i*
> depends: ieee80211
> vermagic: 2.6.20-16-generic SMP mod_unload 586
> parm: antenna:select antenna (1=Main, 2=Aux, default 0 [both]) (int)
> parm: disable:manually disable the radio (default 0 [radio on]) (int)
> parm: associate:auto associate when scanning (default 0 off) (int)
> parm: auto_create:auto create adhoc network (default 1 on) (int)
> parm: led:enable led control (default 1 on)
>  (int)
> parm: channel:channel to limit associate to (default 0 [ANY]) (int)
> parm: rtap_iface:create the rtap interface (1 - create, default 0) (int)
> parm: mode:network mode (0=BSS,1=IBSS,2=Monitor) (int)
> 
> 
> iwpriv eth1 set_mode 4 
> fixes the issue

------- Comment #8 From 2007-10-14 00:38:26 -------
Hi,

(In reply to comment #0)
> If I transfer data across the wireless link I get about 3Mbytes/s which I'm
> happy with.  If I move with the laptop to an area with poor signal the data rate
> drops off which I expect.  Once the data rate hits about 100Kbytes/s once I move
> back into good signal the rate never increases above 150Kb/s  If I down the
> interface and bring it up again the transfer rate increases.

I encounter the same problem. However, what I noted is that previous to these
connection problems, lots of "CCMP: replay detected" messages show up in the
kernel log. Is this also the case on your setup?

I "fix" it by reloading the ipw3945 module, but next time it encounters I'll
try the iwpriv thing.

Just for the record: I don't only encounter a loss of network throughput
(exactly about ~100kb/sec), but also a higher latency in my ssh sessions.
I didn't test that with ping, though.

Sadly, the "replay detected" messages are now dependent on CONFIG_IEEE80211_DEBUG,
which isn't currently turned on in my setup.
(http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=aeb998c124786e8c7fbd6eab347230469e911872)

Sebastian
------- Comment #9 From 2008-12-08 21:49:16 -------
ipw3945 as a driver has been replaced by iwl3945 in official kernel for a long
time. We suggest to use iwl3945 driver instead of the obsolete ipw3945 driver.
If you have bug, please report it with product=iwlwifi and platform="Intel(R)
Wifi Link 3945". Thanks so much!