[mythtv-users] My upgrade from Mythbuntu 10.10 to 12.04

[Will Dormann]

Hi folks,

I've successfully upgraded my aging Mythbuntu 10.10 box, and I'd like to
share my experience.   Before and during the process, there were a few
things that I had trouble Googling for to find a definitive answer, so I
figure this message may help others.

Last time I attempted to upgrade, I tried the normal over-the-network
dist-upgrade route.  This was quite tedious, as it involved going from
10.10 to 11.04, then 11.04 to 11.10, and then from 11.10 to 12.04.  I
eventually gave up when I got to the point of random hangs involving
"NVRM: os_schedule: Attempted to yield the CPU while in atomic or
interrupt context"
<http://www.mythtv.org/pipermail/mythtv-users/2012-October/342002.html>

Given some new features I'd like to investigate (AC3 audio) and related
bug fixes (e.g. <https://code.mythtv.org/trac/ticket/2077>), I figured
I'd give it another go.   Before attempting anything, I made sure  that
the system was ready for disaster recovery backup/restore.   (dd of mbr,
dump of /boot, xfsdump of root)

Issue #1:  dist-upgrade doesn't work anymore, resulting in a 404 error.
  Probably because the OS version I'm going to (11.04) isn't supported
anymore.  This was probably a blessing in disguise.  I found out that
doing an upgrade install *is* possible, going directly from 10.10 to
12.04 by using the install ISO.  I had heard conflicting reports about
whether or not this is possible.  Going through the install process,
there are some aspects that seemed like a fresh install, as opposed to
an upgrade.   e.g., asking me to create a user account and set a
password, as well as asking what kind of remote I had.  I just created
the same user name and pass, and chose some vaguely-similar remote.

In the end, the upgrade went pretty smoothly.  The original user's home
directory was preserved, and the MythTV database (where pretty much all
of the settings of a MythTV box live) was preserved fine.  I also set up
mythbuntu in the gui config tool to use MythTV 0.27.

Issue #2: One thing I ran into after a short amount of time is the
"allocation failed: out of vmalloc space" bug.  Apparently this is a
common problem on 32bit systems (I only have 2GB of RAM, so I can't
imagine any benefit of going 64-bit.).
<http://www.mythtv.org/wiki/Common_Problem:_vmalloc_too_small>  I first
tried setting 192MB, and that helped, but eventually, I encountered the
dreaded "NVRM: os_schedule: Attempted to yield the CPU while in atomic
or interrupt context" bug again.   After updating to 256MB, I haven't
had a problem.

Issue #3: My remote didn't work anymore.  Given the behavior during
install, this was no surprise.  Just restore /etc/lirc and ~/.lirc from
backup.

Issue #4: My AT TV Wonder 600 wasn't working quite right.  Every second
or so I'd see in dmesg:
lgdt330x: i2c_read_demod_bytes: addr 0x0e select 0x58 error (ret == -19)
As described here <https://www.kernellabs.com/blog/?p=1092> restarting
mythbackend fixes the problem.   My complete hack workaround was to add
to /etc/rc.local:
sleep 30 && /etc/init.d/mythtv-backend restart &
For some reason, if I'd restart mythtv-backend too soon, it wouldn't fix
the problem.   Given how rarely the system is rebooted, I didn't look
into this further.

Issue #5: When going to shutdown or reboot the system, it would go to
the splash screen and just sit there.  I'd have to run "reboot" again
for it to actually reboot.   I later discovered that this was an unclean
reboot as the filesystems weren't unmounted.  To troubleshoot this, I
disabled the splash/quiet stuff in grub:
GRUB_CMDLINE_LINUX_DEFAULT=""
in /etc/default/grub and then sudo update-grub
With this change, I found that it was hanging on K19lirc.  My workaround
here is to remove both /etc/rc0.d/K19lirc and /etc/rc6.d/K19lirc.  I
can't imagine any negative aspect of rebooting without "cleaning up"
lircd, or whatever K19lirc is doing.  But the system reboots fine now.

I think that's about it.  Overall, I'm happy with the upgrade.  The
above may seem like a lot of hassle, but it was easier than I was
expecting.  My primary goal for this rambling message is to seed Google
with certain phrases related to this upgrade.   I've also not yet
checked if mythburn can burn hd-pvr content with 0.27 without patching
<http://www.mythtv.org/pipermail/mythtv-users/2012-October/341879.html>
yet, but given how infrequently I use that feature, I'll get to it
eventually.


-WD