Issue updating from Pi 3B to 3B+. Constant Buffering


I have just upgraded my Pi from a 3B to a 3B+. I am using the same cables and memory card, so quite literally a direct in place replacement. No reinstall or config changes at all.

I first tried this on the March release, and have now upgrade to the current 2020-06-03, (Kodi v18.7), and the result is the same.

I do not have an advancedsetting.xml to override anything.

Running on the the 3B, everything was fine, apart from lack of CPU grunt and overheating when playing HEVC.

Now on the 3B+, everything that I play results in constant ‘Buffering’ messages on screen. Swap the 3B back in and all is fine.

Can anyone suggest anything that I can look at to try and fix this?

To get a better understanding of the problem you are experiencing we need more information from you. The best way to get this information is for you to upload logs that demonstrate your problem. You can learn more about how to submit a useful support request here.

Depending on the used skin you have to set the settings-level to standard or higher, in summary:

  • enable debug logging at settings->system->logging

  • reboot the OSMC device twice(!)

  • reproduce the issue

  • upload the log set (all configs and logs!) either using the Log Uploader method within the My OSMC menu in the GUI or the ssh method invoking command grab-logs -A

  • publish the provided URL from the log set upload, here

Thanks for your understanding. We hope that we can help you get up and running again shortly.

OSMC skin screenshot:

Please, provide log sets from both the 3B and the 3B+ after reboot and directly playing the same movie/video, thx.

Here are the logs in Question: is with the issue on the 3B+. It happened in the file that I started playing at 22.02.19, and occurred several times. I stopped after 8 minutes. is the same file on the 3B. I watched the first 10 minutes starting at 11.20.30 and there were no issues.

Many Thanks

Please look at the time that I gave. The comparison file is the Room 101 episode.

I would suggest copying the Kodi user data directory in its entirety from the other system.

This is the SAME memory card, in both devices.

Apart from a multitude of Kodi-related messages that I don’t really understand, I’ve noticed a few things that I feel able to comment on:

  • The 3B+ log shows that the ethernet interface had an unusually large number (5087) of dropped packets.
  • The video cache size is only 20 MB. In practce, this will provide just 7.5 MB of read-ahead video cache.
  • There was only 90 MB of free memory on the 3B+ and there seemed to be lots of memory allocation error messages. By contrast, the 3B log shows 251 MB free memory.

It’s just a theory, but since the 3B+ has a pseudo-gigabit interface, you might be getting some kind of flow-control issues on the ethernet interface. You have a very small video cache, so it might be that the cache is becoming exhausted because of network delays.

Two possible ways to test this theory:

Increase the cache size in advancedsettings.xml and/or
Reduce the ethernet speed to 100 Mbits/sec (sudo ethtool -s eth0 speed 100 duplex full autoneg off)

I can’t explain the greater memory usage but it might be connected with the first two bullet points.

I will look into adjusting the cache, it just seems strange that the 3B+ should need it when the 3B doesn’t

I’ve already tested forcing the link down to 100Mbs at the switch end, and that made no difference at all.

The low free memory on the 3B+ seems a little odd. I’ll see if I can do some kind of memtest on it in case there might be an issue.

I’ve done a fresh install of osmc onto a new memory card, and copied the the whole of the user directory over.

After that I didn’t notice an issue, but decided to setup a video cache of 96MB which leaves about 30-36MB of free RAM on the 3B+.

Ifconfig doesn’t show any issues with the ethernet anymore either.

It seems like something that is specific to the 3B+ on the original memory card wasn’t right. I don’t know if that could be because the 3B+ didn’t exist when that other card was first setup, or just that something has been corrupted over over time.

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