Kernel image 6.5 (web-)midi problems

[Henning Sprang]

After the update to mantis, I have a problem with (at least - i have not yet researched further issues) Web-Midi applications running in the browser.

Up to Kernel 6.2 it works just fine (also when downgrading the kernel to 6.2 in mantis)to use https://app.electra.one/ http://components.novationmusic.com/ with a web midi enabled browser (must be google chrome installed by deb or chromium installed from their nightly builds or via nixos - because the snap version doesn't properly allow web midi for some reason that I still need to investigate further).

When using any 6.5 or later kernel as included in mantis, or also when building my own from kernel.org, the devices I want to be managed with are basically identified, but no further actions are possible.

This is 100% reproducible, switching back and forth between 6.5+ and 6.2 kernels is very clearly showing the old version always works easily, but the newer version doesn't.
Also a 6.6.1 mainlne kernel from kernel.org still has the issue.

I have fiddled with this quite some hours, I suspected it has something to to with the midi 2.0 change in kernel 6.5 and tried turning it off with module parameters, but also when disabled or compiled a kernel without midi 2.0 support the problem, persists.
The same with the latest 6.6.1 kernel.

I have not found any error output in dmesg or journalctl that seems to be related to the problem so far, and also no other way to try to trigger the problem but the above described web midi thing.

All tests have been done with the ubuntu kernel config - and the mainline configs created with make oldconfig.

So I might additionally test the default mainline configuration, and also later mainline versions like 6.6.2 and try to identify other erratic behaviours in midi usage (of controllers etc) and add information about it... also I did not yet try the normal "generic" kernels, just

Also I found this thing right now:

https://forum.cockos.com/showthread.php?t=283086

at the end it says there has been a bug in the kernel in the midi code.

But I'm not sure if that is the same issue. For one I have not seen similar error messages in my system, but mainly this post says the bug is fixed in 6.5.6 https://lwn.net/Articles/946853/ - and I have tested 6.5.11 mainline form kernel.org with the problem still persisting.
It might be there is some more wrong with the 6.5+ kernels in the midi area.

if there are any further tests or logs needed or helpful, please let me know.

[Henning Sprang (henning)]

I also found this interesting page that discloses that Ubuntu kernel versions like 6.5.0 are not solely based on this version number mainline kernels but really contain much later versions
https://people.canonical.com/~kernel/info/kernel-version-map.html

but there is no version of this for current kernels. So I dont know if that is still the case for todays ubuntu kernels. (if so, this is extremly confusing to always set the minor version to 0 despite it's really anything later and such a map is needed to understand that)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.