8086:422b [Dell Latitude E6520] linux-image-3.11.0-15-generic appears to regress connection speed for iwlwifi

[Carl G]

I recently installed 13.10 and immediately updated to the latest updates via my ethernet work connection.

Got home and noted that linux-image-3.11.0-15-generic was only able to transfer to my local media box via wifi at ~350kB/s (ie. Taking 10+ minutes for a 300Mb file)

After trawling the net for a while, the usual solution appeared to be "restart with 11n_disable=1 as a module option."

That didn't solve the issue not did several other suggestions. So I reverted to the other kernal installed on my system linux-image-3.11.0-12-generic

After booting that kernel my transfer speeds are ~3MB/s - much saner (though I have had things configured so I get closer to 6MB/s)

Not sure what other info I can provide.

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: linux-image-3.11.0-12-generic 3.11.0-12.19 [modified: boot/vmlinuz-3.11.0-12-generic]
ProcVersionSignature: Ubuntu 3.11.0-12.19-generic 3.11.3
Uname: Linux 3.11.0-12-generic x86_64
ApportVersion: 2.12.5-0ubuntu2.2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: carlos 2193 F.... pulseaudio
 /dev/snd/controlC0: carlos 2193 F.... pulseaudio
Date: Fri Jan 17 23:59:56 2014
HibernationDevice: RESUME=UUID=0fbe8395-5e8d-430f-823c-b5408451c73e
InstallationDate: Installed on 2014-01-14 (3 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1)
MachineType: Dell Inc. Latitude E6520
MarkForUpload: True
ProcEnviron:
 LANGUAGE=en_AU:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_AU.UTF-8
 SHELL=/bin/bash
ProcFB:
 0 inteldrmfb
 1 nouveaufb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.11.0-12-generic root=UUID=22c75466-3cb5-416a-9513-8debe4246bcd ro quiet splash vt.handoff=7
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
 linux-restricted-modules-3.11.0-12-generic N/A
 linux-backports-modules-3.11.0-12-generic N/A
 linux-firmware 1.116
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/11/2012
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A14
dmi.board.name: 0J4TFW
dmi.board.vendor: Dell Inc.
dmi.board.version: A01
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA14:bd07/11/2012:svnDellInc.:pnLatitudeE6520:pvr01:rvnDellInc.:rn0J4TFW:rvrA01:cvnDellInc.:ct9:cvr:
dmi.product.name: Latitude E6520
dmi.product.version: 01
dmi.sys.vendor: Dell Inc.

[Brad Figg (brad-figg)]

This change was made by a bot.

[Joseph Salisbury (jsalisbury)]

The 3.11.0-17.28 kernel is now available in the -proposed repository. Would it be possible for you to test this latest kernel and post back if it resolves this bug?
See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed.

Thank you in advance!

[Joseph Salisbury (jsalisbury)]

If the bug still exits in 3.11.0-17, please change the status back to confirmed.

[Carl G (carl-gherardi)]

The package doesn't seem to have pushed out yet - direct download link?

[Carl G (carl-gherardi)]

The kernel still isn't public, but part of the issue appears to be my router - Once a couple of failures have happened, i'm then unable to get known 'good' configurations working.

Good:
3.11.0-12-generic using firmware:
[ 4679.763448] iwlwifi 0000:03:00.0: loaded firmware version 9.221.4.1 build 25532 op_mode iwldvm
# iwconfig wlan0
wlan0 IEEE 802.11abgn ESSID:"Envy"
          Mode:Managed Frequency:2.437 GHz Access Point: <mac>
          Bit Rate=270 Mb/s Tx-Power=15 dBm
          Retry long limit:7 RTS thr:off Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=69/70 Signal level=-41 dBm
          Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
          Tx excessive retries:1257 Invalid misc:90 Missed beacon:0
I'm getting transfer speeds > 3MB/s

I'll post bad after a reboot of both router and laptop in a couple of hours.

[Øyvind Stegard (oyvindstegard)]

I confirm this issue. In my case there is a huge regression in uplink speed with kernel 3.11.0-15-generic compared to 3.11.0-12-generic (which is good).

With 3.11.0-15-generic, I only get sustained 400–500KB/s uplink speed (downlink speed is better though).

With 3.11.0-12-generic the uplink speed is over 7MB/s sustained (and over 11MB/s downlink rate).

I have an Asus RT-AC66U router with N-capabilities, but no tweaking on router helps on the iwlwifi speed problem when running the 3.11.0-15-generic kernel. I also see the problem with other access points.

My wifi card:
       description: Wireless interface
       product: Centrino Advanced-N 6200
       vendor: Intel Corporation
       physical id: 0
       bus info: pci@0000:03:00.0
       logical name: wlan0
       version: 35
       serial: 00:23:14:a8:0e:c0
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=iwlwifi driverversion=3.11.0-12-generic firmware=9.221.4.1 build 25532 ip=192.168.1.100 latency=0 link=yes multicast=yes wireless=IEEE 802.11abgn
       resources: irq:44 memory:d6e00000-d6e01fff

wlan0 IEEE 802.11abgn ESSID:"Kaffefilter5G"
          Mode:Managed Frequency:5.2 GHz Access Point: BC:EE:7B:7C:DC:E4
          Bit Rate=6 Mb/s Tx-Power=15 dBm
          Retry long limit:7 RTS thr:off Fragment thr:off
          Power Management:on
          Link Quality=64/70 Signal level=-46 dBm
          Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
          Tx excessive retries:290304 Invalid misc:65 Missed beacon:0

No special iwlwifi module options. Fully updated Ubuntu 13.10 x86-64.

[Øyvind Stegard (oyvindstegard)]

With mainline kernel from http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.11.10.3-saucy/, the iwlwifi transfer speeds are good again (in both directions).

[penalvch (penalvch)]

Carl G, thank you for reporting this and helping make Ubuntu better. Could you please confirm this issue exists with the latest development release of Ubuntu? ISO images are available from http://cdimage.ubuntu.com/daily-live/current/ . If the issue remains, please just make a comment to this.

[penalvch (penalvch)]

Øyvind Stegard, thank you for your comment. So your hardware and problem may be tracked, could you please file a new report with Ubuntu by executing the following in a terminal while booted into a Ubuntu repository kernel (not a mainline one) via:
ubuntu-bug linux

For more on this, please read the official Ubuntu documentation:
Ubuntu Bug Control and Ubuntu Bug Squad: https://wiki.ubuntu.com/Bugs/BestPractices#X.2BAC8-Reporting.Focus_on_One_Issue
Ubuntu Kernel Team: https://wiki.ubuntu.com/KernelTeam/KernelTeamBugPolicies#Filing_Kernel_Bug_reports
Ubuntu Community: https://help.ubuntu.com/community/ReportingBugs#Bug_reporting_etiquette

When opening up the new report, please feel free to subscribe me to it.

Thank you for your understanding.

Helpful bug reporting tips:
https://wiki.ubuntu.com/ReportingBugs

[Carl G (carl-gherardi)]

Hi penalvch, I'm still awaiting on 3.11.0-17 to appear in the proposed repository. I've enabled the proposed repo for Saucy.

https://www.google.com.au/search?q=site:http:%2F%2Farchive.ubuntu.com+linux-image-3.11.0-17-generic isn't showing any results either.

[penalvch (penalvch)]

Carl G, just to clarify, when you tested Trusty as requested in https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1270208/comments/9 , did the connection speed improve?

[Carl G (carl-gherardi)]

I was following jsalisbury's instructions.

penalvch - I dont have a burner handy so testing using a bootable cd/dvd is out. I'm happy to install and uninstall a kernel deb to test the Trusty kernel if you can point me at the packages directly.

[penalvch (penalvch)]

Carl G, would you have a USB drive?

[Carl G (carl-gherardi)]

Ok, installed http://cdimage.ubuntu.com/daily-live/current/trusty-desktop-amd64.iso onto a USB drive, booted and was able to get up to 3MB/s performing the same smb transfer to my media box as the original post.

Impirically slower than 3.11.0-12, but seemed stable enough.

[penalvch (penalvch)]

Carl G, would you need a backport to a release prior to Trusty, or may this be closed as Status Invalid?

[Carl G (carl-gherardi)]

I'm not sure I understand the question.

The current Saucy kernel 3.11.0-15 is unusable for me, and i'm forced to boot into 3.11.0-12.

That is clearly a regression and not Invalid surely?

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]

[penalvch (penalvch)]

Carl G:
>"I'm not sure I understand the question."

A backport is a fix from a later release where the problem doesn't occur, in a release where the problem does. Given Saucy EOLs in ~4 months, you may want to begin using Trusty going forward. Despite this, you may indicate your desire for a backport via a comment.

>" The current Saucy kernel 3.11.0-15 is unusable for me, and i'm forced to boot into 3.11.0-12. >"That is clearly a regression..."

That was already noted in the Bug Description, and via the Tag I assigned to this report:
regression-update

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]

[Andrew Gunnerson (cxl)]

The fix for this is to add the following to /etc/modprobe.d/iwlwifi.conf

    options iwlwifi 11n_disable=8

The problem was caused by the following commit, which disabled TX aggregation by default on the "old" hardware managed by the iwldvm driver (including our Intel 6300AGN): https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=205e2210daa975d92ace485a65a31ccc4077fe1a

Looking at the commit and output of "modinfo iwlwifi", passing the value 8 to the 11n_disable parameter forces TX aggregation to be enabled again.

After some basic testing, this has boosted my (upload) transfer speed from ~20 Mbps to ~100 Mbps (or equivalently, from ~2.5 MB/s to ~ 12 MB/s).

[penalvch (penalvch)]

Xiao-Long Chen, thank you for your comment. So your hardware and problem may be tracked, could you please file a new report with Ubuntu by executing the following in a terminal while booted into the default Ubuntu kernel (not a mainline one) via:
ubuntu-bug linux

For more on this, please read the official Ubuntu documentation:
Ubuntu Bug Control and Ubuntu Bug Squad: https://wiki.ubuntu.com/Bugs/BestPractices#X.2BAC8-Reporting.Focus_on_One_Issue
Ubuntu Kernel Team: https://wiki.ubuntu.com/KernelTeam/KernelTeamBugPolicies#Filing_Kernel_Bug_reports
Ubuntu Community: https://help.ubuntu.com/community/ReportingBugs#Bug_reporting_etiquette

When opening up the new report, please feel free to subscribe me to it.

Thank you for your understanding.

Helpful bug reporting tips:
https://wiki.ubuntu.com/ReportingBugs

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]