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Thread: 12.04 - Intel's 4965 wireless high packet loss

  1. #1
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    12.04 - Intel's 4965 wireless high packet loss

    Greetings, we get very high packet loss with that wireless card in Ubuntu 12.04. The problem is not present in WinXP on the same computer - MSI EX700. The following is just after opening two or three web pages:

    Code:
    ~$ sudo iwconfig wlan0
    wlan0     IEEE 802.11abg  ESSID:"amu"  
              Mode:Managed  Frequency:2.462 GHz  Access Point: 00:78:9E:FA:32:C8   
              Bit Rate=54 Mb/s   Tx-Power=15 dBm   
              Retry  long limit:7   RTS thr:off   Fragment thr:off
              Encryption key:off
              Power Management:off
              Link Quality=55/70  Signal level=-55 dBm  
              Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
              Tx excessive retries:5  Invalid misc:1073   Missed beacon:0
    If Transmission is on, wireless becomes unusable, and the number of lost packets spikes into hundreds of thousands in minutes.

    I know that the card is troublesome, and have already added the 11n_disable=1 option, and also disabled ipv6, just in case, but none of that helped with the packet loss. Is there anything else we can try?

    Code:
    ~$ lsmod | grep iwl4965
    iwl4965               117368  0 
    iwl_legacy             71134  1 iwl4965
    mac80211              436455  2 iwl4965,iwl_legacy
    cfg80211              178679  3 iwl4965,iwl_legacy,mac80211
    Code:
    :~$ modinfo iwl4965
    filename:       /lib/modules/3.2.0-26-generic/kernel/drivers/net/wireless/iwlegacy/iwl4965.ko
    firmware:       iwlwifi-4965-2.ucode
    alias:          iwl4965
    license:        GPL
    author:         Copyright(c) 2003-2011 Intel Corporation <ilw@linux.intel.com>
    version:        in-tree:
    description:    Intel(R) Wireless WiFi 4965 driver for Linux
    srcversion:     CBC919AF7D4741EB822BF5F
    alias:          pci:v00008086d00004230sv*sd*bc*sc*i*
    alias:          pci:v00008086d00004229sv*sd*bc*sc*i*
    depends:        iwl-legacy,cfg80211,mac80211
    intree:         Y
    vermagic:       3.2.0-26-generic SMP mod_unload modversions 686 
    parm:           swcrypto:using crypto in software (default 0 [hardware]) (int)
    parm:           queues_num:number of hw queues. (int)
    parm:           11n_disable:disable 11n functionality (int)
    parm:           amsdu_size_8K:enable 8K amsdu size (int)
    parm:           fw_restart:restart firmware in case of error (int)
    Code:
    ~$ dmesg | grep iwl
    [   18.469448] iwl4965: Intel(R) Wireless WiFi 4965 driver for Linux, in-tree:
    [   18.469452] iwl4965: Copyright(c) 2003-2011 Intel Corporation
    [   18.469537] iwl4965 0000:06:00.0: PCI INT A -> GSI 19 (level, low) -> IRQ 19
    [   18.469574] iwl4965 0000:06:00.0: setting latency timer to 64
    [   18.469626] iwl4965 0000:06:00.0: Detected Intel(R) Wireless WiFi Link 4965AGN, REV=0x4
    [   18.513077] iwl4965 0000:06:00.0: device EEPROM VER=0x36, CALIB=0x5
    [   18.514328] iwl4965 0000:06:00.0: Tunable channels: 13 802.11bg, 19 802.11a channels
    [   18.514479] iwl4965 0000:06:00.0: irq 47 for MSI/MSI-X
    [   18.550935] iwl4965 0000:06:00.0: loaded firmware version 228.61.2.24
    [   18.555546] ieee80211 phy0: Selected rate control algorithm 'iwl-4965-rs'
    [  100.571926] iwl4965 0000:06:00.0: RF_KILL bit toggled to enable radio.
    Code:
    ~$ lspci -nnk | grep -iA2 net
    06:00.0 Network controller [0280]: Intel Corporation PRO/Wireless 4965 AG or AGN [Kedron] Network Connection [8086:4229] (rev 61)
    	Subsystem: Intel Corporation PRO/Wireless 4965 AG or AGN [8086:1101]
    	Kernel driver in use: iwl4965

  2. #2
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    Re: 12.04 - Intel's 4965 wireless high packet loss

    bump

  3. #3
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    Re: 12.04 - Intel's 4965 wireless high packet loss

    @mikewhatever,

    You might want to check into the MTU size.

    https://en.wikipedia.org/wiki/Maximum_transmission_unit

    I did have to change mine from the default 1500 to 1492 to lessen packet losses.

  4. #4
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    Re: 12.04 - Intel's 4965 wireless high packet loss

    bkratz, do you have the same hardware? Whay do you think chanching MTU should help.

  5. #5
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    Re: 12.04 - Intel's 4965 wireless high packet loss

    Quote Originally Posted by mikewhatever View Post
    bkratz, do you have the same hardware? Whay do you think chanching MTU should help.


    No, I do not have the same hardware--just a similar occurrence in the past where I had many tx errors show up and experimentally found that they disappeared at lower mtu sizes. This was on dsl--my cable modem connects correctly with 1500.

  6. #6
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    Re: 12.04 - Intel's 4965 wireless high packet loss

    Hi, I suggest adding:
    Code:
    options iwl3945 swcrypto=1
    Thanks

  7. #7
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    Re: 12.04 - Intel's 4965 wireless high packet loss

    bkratz, yes, dsl modems are known to use mtu=1492, but I have a cable one. I also believe it's the driver problem, however, if you think of anything else, please post, as I am pretty desperate by now.

    wildmanne39, thanks for your input. I've actually tried swcrypto, both 1 and 0 just a few days ago, (options iwl4965 swcrypto=1, to be precise) but I'll try again.

    I've ran another test, downloaded a 101MB file from another machine in the house over wifi, with nothing else going on on the network. It took 5min.

    Code:
    wlan0     IEEE 802.11abg  ESSID:"amu"  
              Mode:Managed  Frequency:2.462 GHz  Access Point: 00:78:9E:FA:32:C8   
              Bit Rate=36 Mb/s   Tx-Power=15 dBm   
              Retry  long limit:7   RTS thr:off   Fragment thr:off
              Power Management:off
              Link Quality=61/70  Signal level=-49 dBm  
              Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
              Tx excessive retries:5  Invalid misc:14603   Missed beacon:0

  8. #8
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    Re: 12.04 - Intel's 4965 wireless high packet loss

    Quote Originally Posted by mikewhatever View Post
    bkratz, yes, dsl modems are known to use mtu=1492, but I have a cable one. I also believe it's the driver problem, however, if you think of anything else, please post, as I am pretty desperate by now.

    wildmanne39, thanks for your input. I've actually tried swcrypto, both 1 and 0 just a few days ago, (options iwl4965 swcrypto=1, to be precise) but I'll try again.

    I've ran another test, downloaded a 101MB file from another machine in the house over wifi, with nothing else going on on the network. It took 5min.

    Code:
    wlan0     IEEE 802.11abg  ESSID:"amu"  
              Mode:Managed  Frequency:2.462 GHz  Access Point: 00:78:9E:FA:32:C8   
              Bit Rate=36 Mb/s   Tx-Power=15 dBm   
              Retry  long limit:7   RTS thr:off   Fragment thr:off
              Power Management:off
              Link Quality=61/70  Signal level=-49 dBm  
              Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
              Tx excessive retries:5  Invalid misc:14603   Missed beacon:0


    Had another thought--have you considered "playing" with the bit rate and transmit power? directions can be found in the terminal under "man iwconfig".

  9. #9
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    Re: 12.04 - Intel's 4965 wireless high packet loss

    Hi, I believe you can use both of those options at the same time like this:
    Code:
    options iwl3945 swcrypto=1 11n_disable=1
    check your sys/logs for errors like in this link.
    http://ubuntuforums.org/showthread.p...ighlight=Intel
    Thanks

  10. #10
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    Re: 12.04 - Intel's 4965 wireless high packet loss

    I've tried locking wlan0 to the 54Mbps rate:

    sudo iwconfig wlan0 rate 54M

    It worked for a few minutes, then disconnected, and wouldn't reconnect until the module is reloaded or the rate reset to auto. The symptoms with are trying to deal with remained.

    swcrypto=1 doesn't seem to affect anything either way. It seems, not matter what it's set to, the driver always defaults to software crypto
    Last edited by mikewhatever; July 29th, 2012 at 02:20 PM.

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