steps in bisecting the kernel

[Lars Noodén]

I am trying to track down a trackpad bug that started after the 2.6.35-22 kernel in 10.10 and before the 2.6.38-8 kernel in 11.04. I am told that to bisect the kernel is the way to go.

In the bisection instructions an example is given:

git log --oneline Ubuntu-2.6.35-24.42..Ubuntu-2.6.35-25.43

How do I calculate the right values for git based on the two known kernels (2.6.35-22 and 2.6.38-8) I have?

[Doug S]

Hi Lars,

I think before you go to the git step. you want further isolate where the issue got introduced by testing more kernels from https://launchpad.net/ubuntu/maverick/+source/linux
and /or
https://launchpad.net/ubuntu/natty/+source/linux (scroll down to the "Releases in Ubuntu" section)

Oh, I see similar notes have been added to lauchpad bug report you linked to above. I was gone for quite some time trying to figure out this reply, and I guess you made progess in the meantime. Myself, I find this stuff a little slow and tedious to try to find and follow. Hope you get it isolated.

[Lars Noodén]

Thanks.

I think I've found how to navigate https://launchpad.net/ubuntu/maverick/+source/linux through to the versions of the kernel I need to test.

[Lars Noodén]

I've gotten through the kernels that were available for download.

2.6.35-32.67, if it overwrote 2.6.35-32.64 when I installed it, was good.

2.6.38-10.44 was definitely bad.

What is the next step in the bisect? I've tried followng the example, but get the error below.

$ git log --oneline Ubuntu-2.6.35-32.67..Ubuntu-2.6.38-10.44
fatal: ambiguous argument 'Ubuntu-2.6.35-32.67..Ubuntu-2.6.38-10.44': unknown revision or path not in the working tree.
Use '--' to separate paths from revisions

[Doug S]

Wouldn't you switch to the natty kernels and continue to try to isolate?
I would start with 2.6.36-0.1 as a starting point for the natty successive approximation. If that works then 2.6.37-8.21 as an approximate mid-point of the 42 or 43 kernels in between, and so on...

[Lars Noodén]

Thanks. I've gotten it narrowed down to the last good one as 2.6.38-7.39 and the first bad one as 2.6.38-8.40.

https://wiki.ubuntu.com/Kernel/Kerne...ernel_versions

I'm able to clone the branch:

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

and create a bisect

git checkout -b mybisect origin/master

However, I can't get through the next step.

git bisect start Ubuntu-2.6.38-8.40..Ubuntu-2.6.38-7.39
git bisect start Ubuntu-2.6.38-8.40 Ubuntu-2.6.38-7.39

It should say something about bisecting and the number of revisions left. But it produces no output or anything like in the instructions. If I try the statement again, it replies with, "Already on 'mybisect'"

Edit: It was the double dots that were wrong.