Ubuntu
linux package

Severe packet loss with Atheros Wi-Fi and lucid kernel

Bug #573689 reported by Jon Kåre Hellan
10
This bug affects 2 people
Affects Status Importance Assigned to Milestone
linux (Ubuntu)
Fix Released
Undecided
Unassigned

Bug Description

With the lucid kernel, linux-image-2.6.32-21-generic, I'm seeing severe packet loss using Atheros wireless cards.
The loss is about 10%. This severely impacts network performance.

There was no packet loss with lucid and the Ubuntu kernel from karmic, nor with lucid and a kernel.org 2.6.33.3 kernel.
2.6.33.3 was built using make oldconfig and default answers to the new config options. Neither was there packet loss with
a Debian live CD running 2.6.32.

With the lucid kernel, I saw the same packet loss using both the ath5k driver and madwifi snapshots from September 2009 and
March 2010.

3 different Atheros cards showed the same packet loss: An external D-Link AG650, and two different mini-pci cards for Thinkpad T42p. lspci describes the one i'm currently using as: "02:02.0 Ethernet controller: Atheros Communications Inc. AR5212 802.11abg NIC (rev 01)" - PCI ID 168c:1014. I don't have other types of wireless cards available, apart from an old Orinoco, which didn't work with Lucid.

I'm running a Thinkpad T42p with a 32 bit x86 Pentium M CPU.

Obviously, this is no radio interference problem, as I'm seeing literally zero loss over 1000 pings with other kernels.

I've solved the problem for myself, but it may affect others.

Revision history for this message
Renate (yollywau) wrote :

It may be, that the packet loss of ath5k is the reason for this bug. https://bugs.launchpad.net/ubuntu/+bug/570375.

Thunderbird could not be sent because the connection to SMTP server mail.gmx.net was lost in the middle of the transaction. (a mail with attach). It works with the driver of http://snapshots.madwifi-project.org/madwifi-trunk-current.tar.gz.

Revision history for this message
Jeremy Foshee (jeremyfoshee) wrote :

Hi Jon,

Please be sure to confirm this issue exists with the latest development release of Ubuntu. ISO CD images are available from http://cdimage.ubuntu.com/releases/ . If the issue remains, please run the following command from a Terminal (Applications->Accessories->Terminal). It will automatically gather and attach updated debug information to this report.

apport-collect -p linux 573689

Also, if you could test the latest upstream kernel available that would be great. It will allow additional upstream developers to examine the issue. Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag. This can be done by clicking on the yellow pencil icon next to the tag located at the bottom of the bug description and deleting the 'needs-upstream-testing' text. Please let us know your results.

Thanks in advance.

    [This is an automated message. Apologies if it has reached you inappropriately; please just reply to this message indicating so.]

tags: added: needs-kernel-logs
tags: added: needs-upstream-testing
tags: added: kj-triage
Changed in linux (Ubuntu):
status: New → Incomplete
Revision history for this message
Jon Kåre Hellan (hellan) wrote :

As I wrote in the original report, the issue is in the released kernel in Lucid - linux-image-2.6.32-21-generic 2.6.32-21.32.

It is not in Lucid userland running over a Karmic kernel.

It is not in Lucid userland running over the kernel.org 2.6.33.3 kernel, configured with make oldconfig based on the
Lucid kernel config, default answer to all new options.

Do you want me to test a mainline 2.6.32 kernel? I can test the latest from kernel.org, or v2.6.32.11-lucid from the mainline kernels archive. According to the table, 2.6.32-21.32 corresponds to 2.6.32.11+drm33.2, but I don't see that in the mainline kernels archive.

Revision history for this message
Jon Kåre Hellan (hellan) wrote :

This no longer happens in 2.6.32-22. Can close.

Jeremy Foshee (jeremyfoshee)
Changed in linux (Ubuntu):
status: Incomplete → Fix Released
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