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

Neil Salstrom salstrom at gmail.com
Sun Feb 24 02:15:16 UTC 2013


On Fri, Feb 22, 2013 at 11:29 PM, Neil Salstrom <salstrom at gmail.com> wrote:
> Has anyone else noticed problems watching DVD's using a 3.7.x kernel
> or a 3.8.x kernel?  I first noticed the problem a while back and
> started this thread:
>
> http://www.gossamer-threads.com/lists/engine?do=post_view_flat;post=537334;list=mythtv
>
> It seemed to be related to using the 3.7 series kernel at that time
> but now with 3.8 out I get the same problem.  It only affects (as far
> as I can tell) DVD's played from the physical disk or a full .iso of
> the physical disk.  A .mkv from the main feature has no problems.
>
> Switching back to a 3.6.x kernel or earlier fixes the problem.  Oddly,
> I can only get the issue to happen in MythTV and not in any other
> playback program.  It happens regardless of playback method as well
> (VDPAU, OpenGL, etc).  This evening I tried a self compiled 3.8.0
> kernel as well as a generic 3.8.0 .deb kernel from Ubuntu.
>
> Looking at the 3.7 change log the only thing that sticks out is:
>
> Filesystems:
> UDF:
>
> Add support for O_DIRECT
> Add "writepages" support for UDF for improved write performance
>
> Could either O_DIRECT or writepages cause this?  I know nothing about
> this topic so I'm just stabbing in the dark here.  Anyone have any
> ideas?  Any way to turn off these two items in 3.8.0 to test?
>
> Thanks,
>
> Neil

Ok, I tried an experiment by compiling 3.8 using the 3.6.11 UDF files
which were changed starting in 3.7:

arch/um/os-Linux/time.c
fs/udf/file.c
fs/udf/inode.c

This removed both the support for O_DIRECT and writepages in my
compiled 3.8.0 kernel.  It compiled and installed successfully.
Sadly, it did not fix the stuttering issues.  Moved back to 3.6.11 and
all is fine...

Not sure where to go from here.  I'm focusing on the UDF portion of
the kernel because it only affects DVD's and nothing else.

Suggestions on trying to figure out why 3.7 or above breaks DVD playback?

Thanks!


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