[mythtv-users] Caveats in upgrading from Ubuntu 18.04 + MythTV 29.1 to something newer?

Will Dormann wdormann at gmail.com
Tue Apr 25 01:43:34 UTC 2023

On 3/9/23 6:27 PM, Will Dormann wrote:
> Is there a resource out there that covers the various things that may 
> break as the result of doing such an update (both MythTV and Ubuntu, if 
> I had my wishes), and what can be done to prevent/correct them? 
> Obviously I'll have a full system backup before going down this path, 
> but I'd like to avoid surprises and the related time sinks.

Just an update for the benefit of anybody else who may be in a similar 
boat.  Obviously, my MythTV machine lineage and configuration won't 
match what else is out there, but here was my experience FWIW:

 From Ubuntu 18.04 to 20.04, and MythTV 2:29.1+fixes to 2:31.0+fixes (at 
the same time):

Surprisingly, this double upgrade went mostly without issue at all!  The 
only thing that didn't work was after the upgrade mysqld wasn't 
starting. This seems to be due to me at some point optimizing the mysql 
performance, adding mysql config options that were dropped.  Fixing this 
involved looking at what option was not recognized, removing it, and 
trying again.  If memory serves me correctly, options were both in 
/etc/mysql/my.cnf and /etc/mysql/conf.d/mythtv.conf

 From Ubuntu 20.04 to 22.04:

This was much more problematic.
First, the nvidia drivers weren't loading.  Despite what a google search 
suggested, "sudo apt install xserver-xorg-video-nvidia-525" is what 
fixed it.  "sudo apt install nvidia-driver-525 nvidia-dkms-525" led to 
some weirdness with the proprietary nvidia driver *not* being used by 
Xorg.  I also had to "sudo apt install flex bison" along the way, as 
somehow in the OS upgrade, I ended up without the ability to compile the 
nvidia modules.

Apache also wasn't running.  I had to "sudo a2dismod php7.4" to get it 
to start OK.

After the above steps (which took more time to figure out than I'd like 
to admit), the resulting MythTV box was not ideal in two ways:

1) The deinterlacing with the 525 drivers was noticeably *worse* than 
the nvidia 390 drivers that Ubuntu 20.04 was fine with.  I think 
switching to NVDEC for decoding made it better.  But I'm not convinced 
that the deinterlacing is better than what VDPAU got me with older 
driver versions.

2) I have a cable box that it controlled by 6200ch. For some reason, 
after the upgrade to Ubuntu 22.04, this channel changing script was not 
behaving well. Upon changing the channel (e.g. via clicking on a 
different channel using the MythTV channel guide), the resulting channel 
was some combination of a completely wrong channel, not-in-HD, or some 
strange menu / PPV screen from my cable box.  I couldn't even notice an 
off-by-one or dropped-character issue, as from what I can recall, trying 
to select channel 600 would get me to channel 24, for example.  Running 
6200ch from a terminal worked 100% of the time, every time.  Why there'd 
be a difference between MythTV invoking 6200ch and me invoking it from a 
shell is beyond me.  But given the seemingly asynchronous nature of the 
channel changing and the HD-PVR recording, some channel changes resulted 
in the HD-PVR getting out of sync and choked up and dumping me back to 
the MythTV menu.

I spent a decent amount of time troubleshooting this, but ended up 
restoring to the backup that I made after the 20.04 upgrade.  And 
everything is back to normal.

I suppose I'm vaguely interested in what exactly caused the problems I 
encountered with this upgrade. As far as I can tell, both my 20.04 and 
22.04 experiments both used the exact same version of the MythTV 
packages.  So apparently something at the OS level is at fault here. 
But at least I've bought myself 2 years here in the process.


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