[mythtv-users] MythTV problems with 3.7.x and 3.8.x kernel

Larry Finger Larry.Finger at lwfinger.net
Sun Feb 24 16:48:11 UTC 2013


On 02/23/2013 11:56 PM, Karl Newman wrote:
>
> Since you're set up to compile and use your own kernel, you might try a bisect
> to find the offending commit. Here's the documentation:
> http://www.kernel.org/pub//software/scm/git/docs/git-bisect.html In your case
> you should start with the first 3.6.0 kernel and the first "bad" 3.7 kernel
> (3.7.0?). Based on my limited knowledge about kernel development practices, I
> believe that will minimize the number of commits between the good and bad trees.
> Ideally you would find a bad commit which could be reported upstream to the
> linux kernel list, but if they don't confirm it as a bug, at the least you could
> create a reverse patch that you could apply which would remove the problematic
> commit for your custom kernel and then the mythtv devs could look at it on their
> end. I've done this once and it took about 12 iterations to find the commit
> which caused my problem (not mythtv related).

I work in driver development for wireless devices and need to work with the 
latest cutting-edge kernels. As such, I have bisected for regressions many 
times. Note: The mainline tree only knows about the .0 version - any follow-on 
fixes are kept in a separate repository. Mainline refers to versions as v3.7, 
not v3.7.0.

The 'git bisect' tool is very powerful; however, when bisecting between releases 
such as 3.6 and 3.7, the first set of commits frequently cause the most problems 
with build errors and run-time faults that have nothing to do with the bug under 
investigation. I would suggest starting with the git command 'git checkout 
v3.7-rc1'. If the resulting kernel is OK, then you bisect between v3.7 (bad) and 
v3.7-rc1 (good) and you will avoid the worst of those problems. If -rc1 has the 
problem with the DVD, then the bad version is v3.7-rc1 and good is v3.6.

Good luck,

Larry






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