regression: wifi with AR242x doesn't work with 2.6.27-7 (nor -3,4,5,6), did work with 2.6.27-2

The upgrade to 2.6.27-4 doesn't resolve the problem
Linux portant 2.6.27-4-generic #1 SMP Mon Sep 22 04:40:15 UTC 2008 x86_64 GNU/Linux

I have the same problem with my Sony Vaio VGN-N21S

$ uname -a
Linux sincity 2.6.27-4-generic #1 SMP Wed Sep 24 01:29:06 UTC 2008 x86_64 GNU/Linux

$ lspci | grep Atheros
06:00.0 Ethernet controller: Atheros Communications Inc. AR242x 802.11abg Wireless PCI Express Adapter (rev 01)

Hi Guys,

Would either of you be willing to perform a git bisect between the 2.6.27-2 and 2.6.27-4 kernel to help narrow down the offending patch which caused the regression. Let me know and I can try to walk you through the process - it's definitely not something we expect you to know how to do. The following docs contain some information that may help. Thanks.

http://www.kernel.org/doc/local/git-quick.html#bisect
https://help.ubuntu.com/community/Kernel/Compile

Hi,
I sure want to help you fix the problem. I haven't done this before but it's a good manner to start, isn't it? I'll have time to do that on Sunday.

As the problem happened with the transition from 2.6.27-2 to 2.6.27-3, the git bisect should be done between those two versions.

I suppose I need to have the sources, so I would need to perform:
sudo apt-get build-dep linux-image-2.6.27-2
apt-get source linux-image-2.6.27-2

and

sudo apt-get build-dep linux-image-2.6.27-3
apt-get source linux-image-2.6.27-3

When I have the sources (btw, In synaptics, I don't see linux-image-2.6.27-2 anymore and it's removed from my system), how can I then perform the bisect? In what directory should I have to run the commands below?

# git bisect start
# git bisect bad $linux-image-2.6.27-3
# git bisect good $linux-image-2.6.27-2

And what about linux-ubuntu-modules ? Should I do the same with it?

What would be easier for me is to have a step by step explaination of what I exactly need to do.
Thanks for your help!

Hi Antoine,

Sorry I didn't get back to you before the weekend. Lets see if I can give you a step by step set of directions for performing the bisect the next time you'll have some free time. Again, I really appreciate you willing to do the git bisect. The best (and probably easiest) way to get the Ubuntu kernel source it to clone the ubuntu-intrepid git tree:

git clone git://kernel.ubuntu.com/ubuntu/ubuntu-intrepid.git

You'll then run the git bisect from the ubuntu-intrepid git tree you just cloned:

cd ubuntu-intrepid
git bisect start
git bisect good Ubuntu-2.6.27-2.3
git bisect bad Ubuntu-2.6.27-3.4

Ubuntu-2.6.27-2.3 and Ubuntu-2.6.27-3.4 are the git tags marking each release in the git tree. To see a list of the Ubuntu tags to choose from you can do: git tag -l "Ubuntu-*"

At this point you're ready to start building and testing the kernel. https://help.ubuntu.com/community/Kernel/Compile should outline how to build the kernel from the git tree - make sure you've installed the packages it lists at that page. Then basically do the following (from inside the ubuntu-intrepid directory):

AUTOBUILD=1 NOEXTRAS=1 fakeroot debian/rules binary-generic

Once the build finishes, it should have produced two .deb files in the directory above ubuntu-intrepid. Install these .debs:

cd ..
sudo dpkg -i linux-headers-2.6.27-2-generic_2.6.27-2.3_i386.deb
sudo dpkg -i linux-image-2.6.27-2-generic_2.6.27-2.3_i386.deb

Then you should be able to just reboot and choose the kernel you just built and installed. Once you've booted, verify if wifi is working or not. If it is working, go back to the ubuntu-intrepid git tree and mark that bisect as good. If it is not working mark the bisect as bad:

cd ubuntu-intrepid
git bisect good

--or--

cd ubuntu-intrepid
git bisect bad

You'll then continue this process of building and testing the kernel and marking each with either a git bisect good or git bisect bad until it finally tells you which commit is the bad commit. I'm guessing you'll only need to do a few iterations to narrow down the bad commit since you had already pretty closely narrowed down which versions you noticed the regression.

Once you have narrowed down the patch you should be able to then do:

git bisect reset
git revert <commit id>

Then do one final build to confirm that reverting that patch does indeed resolve the bug. I hope that helps. Just in case what I wrote above isn't exactly clear, I've pasted the execution of the above steps up to installing the first kernel:

ogasawara@emiko:/tmp$ git clone git://kernel.ubuntu.com/ubuntu/ubuntu-intrepid.git
Initialized empty Git repository in /tmp/ubuntu-intrepid/.git/
remote: Counting objects: 910228, done.
remote: Compressing objects: 100% (175290/175290), done.
remote: Total 910228 (delta 752334), reused 891181 (delta 733442)
Receiving objects: 100% (910228/910228), 258.02 MiB | 750 KiB/s, done.
Resolving deltas: 100% (752334/752334), done.
Checking out files: 100% (25052/25052), done.
ogasawara@emiko:/tmp$ cd ubuntu-intrepid/
ogasawara@emiko:/tmp/ubuntu-intrepid$ git bisect start
ogasawara@emiko:/tmp/ubuntu-intrepid$ git bisect goo...

Could be Bug #276508 a duplicate of this one?

I don't think it is. But one experiencing the https://bugs.launchpad.net/bugs/276508 should try intrepid alpha 5 to see if it is working. Then test alpha 6. If this is confirmed, the too bugs could be linked. However, at first sight, I don't think it is since, in this case, no wireless network is detected.

wlan0 No scan results

Hi!
After compiling the kernel, 2 .deb are created. However I have problems when I try to install linux-headers:

antoine@portant 03:55:40:~$ sudo dpkg -i linux-headers-2.6.27-2-generic_2.6.27-2.3_amd64.deb
Selecting previously deselected package linux-headers-2.6.27-2-generic.
(Reading database ... 217824 files and directories currently installed.)
Unpacking linux-headers-2.6.27-2-generic (from linux-headers-2.6.27-2-generic_2.6.27-2.3_amd64.deb) ...
dpkg: dependency problems prevent configuration of linux-headers-2.6.27-2-generic:
 linux-headers-2.6.27-2-generic depends on linux-headers-2.6.27-2; however:
  Package linux-headers-2.6.27-2 is not installed.
dpkg: error processing linux-headers-2.6.27-2-generic (--install):
 dependency problems - leaving unconfigured
Errors were encountered while processing:
 linux-headers-2.6.27-2-generic

The linux-image is installed correctly and I have a new entry in /boot/grub/menu.lst

So the question is: do I need the headers to have to wifi working or should it work without them?

Moreover, I'm not sure I understand that part correctly:

After having tested a kernel, let's say I boot with 2.6.27-2 and wifi works, I do
cd ubuntu-intrepid
bisect good

And after that, what I'm suppose to do? Reexecute the command
AUTOBUILD=1 NOEXTRAS=1 fakeroot debian/rules binary-generic
which 'll then build the kernel with next commit ? Or should I do something else?

Thanks in adavance,

I tried several times to build the kernel but always had the same issue:
 linux-headers-2.6.27-2-generic depends on linux-headers-2.6.27-2; however:
  Package linux-headers-2.6.27-2 is not installed.

A bit of googling and I found this thread on ubuntuforums, maybe some useful info?
http://ubuntuforums.org/showthread.php?p=5953941#post5953941

I just tested the beta of intrepid and wifi is working. So the problem must come from a configuration file.

Per a decision made by the Ubuntu Kernel Team, bugs will longer be assigned to the ubuntu-kernel-team in Launchpad as part of the bug triage process. The ubuntu-kernel-team is being unassigned from this bug report. Refer to https://wiki.ubuntu.com/KernelTeamBugPolicies for more information. Thanks.