just cos you piqued my curiosity...

Have you tried the RPi 4.14 kernel?

commit 0d118e31780349beb5ffa1777fd77058cc464ad6
Author: popcornmix <popcornmix@gmail.com>
Date: Wed Jan 17 13:54:41 2018 +0000

Revert "softirq: Let ksoftirqd do its job"

This reverts commit 4cd13c21b207e80ddb1144c576500098f2d5f882

After the recent vandalisation that thankfully & hopefully ended in a farewell post #15, I feel the need to recap/summarize a little:

I started this thread reporting an issue affecting the official kernel that is delivered by the Raspberry Foundation with their Raspbian images and was only focusing on these official kernels. By not finding any information about this issue at the Raspberry Foundation kernel bug-track (git) and in the Raspbian release notes:
https://downloads.raspberrypi.org/ra...ease_notes.txt
I started to look for help in other places and found the first confirmation in the Kodi Forum and afterwards in a thread at LibreELEC, where the reported issue was also observed and replicated. Finally, by the help of a user (jahutchi), the offending kernel commit that caused this issue was finally found:
https://git.kernel.org/pub/scm/linux...500098f2d5f882
The kernel devs got involved and I was expecting a fix from them, sharing the same approach/expectations like popcornimx (Raspberry Foundation):
https://forum.libreelec.tv/thread/42...6233#post76233
"ideally upstream kernel devs acknowledging the issue introduced and finding a solution"
Linus (Torvalds) came promptly with a fix:
https://patchwork.linuxtv.org/patch/46368/
that wasn't adopted by the Raspberry Foundation - detailed in the following sections.

Meanwhile, a little over a week ago, the folks at Raspberry released their new Raspbian image, I did download it and had no time to check the source code that was used to build its kernel. The only method to obtain the exact source code that I'm aware of implies loading&running the Raspbian on a Pi board and following this guide:
https://github.com/notro/rpi-source/wiki
(mentioned as a link pointing at the Raspberry Forum in my first post in this thread)

I finally checked it now, after a good coffee, and just found out that the folks at Raspberry Foundation reverted the offending commit in their latest kernel release that comes with Raspian:
https://www.raspberrypi.org/downloads/raspbian/
Version: March 2018
Release date: 2018-03-13
Kernel version: 4.9

The exact kernel version after opening the Raspbian image (Kinder Surprise!) is 4.9.80+ and the source code for this kernel build is to be found at (152MB !):
https://github.com/raspberrypi/linux...eace130.tar.gz

Running a diff on the files: /kernel/softirq.c (from the source archive) and the reference from Linus' master at:
https://github.com/torvalds/linux/bl...rnel/softirq.c
got me exactly the offending commit:
https://git.kernel.org/pub/scm/linux...500098f2d5f882

I haven't tested this kernel yet but will do so in the following days. As the offending commit was simply reverted and no patch applied, I don't expect to get into any issues with this new kernel and hope to enjoy the same stability as with my actual (and old) 4.4.50+

It's interesting to follow the development on the softirq.c with the kernel folks (pretty difficult as it spreads over a few threads) and hope they'll come up with a resolution soon that will be generally available and backported/updated.
Just for reference, the kernel devs discussion is to be found in the links from this post:
https://forum.kodi.tv/showthread.php...186#pid2717186

Why, is this a Raspbian forum?

You can get the rpi 4.14 source with
git clone --single-branch -b rpi-4.14.y https://github.com/raspberrypi/linux.git

The firmware has been built against 4.14 since early February and can also be pulled from git

Got the time to load the latest Raspberry Foundation official kernel on Slackware ARM 14.2 & -current:
Kernel: 4.9.80
Firmware: Mar 13 2018 18:45:03, version 6e08617e7767b09ef97b3d6cee8b75eba6d7ee0b (clean) (release)
- that comes with the offending commit reverted:
https://git.kernel.org/pub/scm/linux...500098f2d5f882
And on tvheadend (4.2.5) I still get these - on both SD & HD channels:
I haven't noticed the actual frame drops that might have got resulted from these continuity counter errors in Kodi 17.4, maybe because they are not that many and not occurring that often.
However, I moved back to the well performing kernel 4.4.50 & firmware 3ca4cf4a663c5351eaec08b29d50d6e8324981b4 and will maybe stick with it.
Getting the source code for 4.9.80 from the Raspberry Foundation, applying back the offending commit and then Linus' patch, recompiling the whole kernel in order to test it, might get a little beyond my time availability ATM.
And, there is another recent development - show stopper - for me and my Pi0 (BCM2835) multimedia usage (Kodi), reported here:
https://forum.kodi.tv/showthread.php?tid=326206

I have 3 Raspberry Pi0 boards that I dedicated solely for Multimedia - DVB streaming & Kodi, for all of them I bought a MPEG2 license and recreated the audio schematics from the Pi3B board (analogue audio buffer "sound card"). Given this situation, I'm afraid I'll stick with 4.4.50 until I retire them / throw away / magic smoke will come out of them.

Investigation stopped, issue resolved (was already), kernel devs might come with a fix in the future.

Suggest you don't stop

https://forum.kodi.tv/showthread.php?tid=326206

The 'rpi-4.14.y' branch became the default a few days ago. They've finally moved on from the 4.9 kernel. Hooray!