piCore 13 realtime kernel

[cosminbro]

How can I configure a realtime kernel in piCore 13.1 64 bit?

[Paul_123]

You have to build it yourself.  I quit doing it when the rt patches would not cleanly apply nor yield a stable system.  I haven’t looked in a year or so, but perhaps someone is maintaining a rpi rt kernel source.

[cosminbro]

You have to build it yourself.  I quit doing it when the rt patches would not cleanly apply nor yield a stable system.  I haven’t looked in a year or so, but perhaps someone is maintaining a rpi rt kernel source.

The problem is I can't find the realtime patches for kernel 5.10.77 (piCore 64 13.1), nor kernel 6.1.25 (piCore 64 14.0).
https://wiki.linuxfoundation.org/realtime/start

[cosminbro]

The newest piCore 8 with kernel 4.4.39 has realtime patch available, but I think this kernel it's too old....

[Paul_123]

Start here https://wiki.linuxfoundation.org/realtime/preempt_rt_versions. You will have to apply the rt patches against the rpi kernel tree.   It is not easy.

[cosminbro]

Ok, the latest rt patch for kernel 6.1 is https://cdn.kernel.org/pub/linux/kernel/projects/rt/6.1/patch-6.1.33-rt11.patch.xz

My question is, if piCore 14 64bit has kernel 6.1.25, which patch should by apply from 6.1 folder (https://cdn.kernel.org/pub/linux/kernel/projects/rt/6.1/) ? Should I apply the latest patch, respectivelly patch-6.1.33-rt11.patch.xz ?

Thanks

[Paul_123]

You are going to have to build the kernel and modules anyway.  Just pull the matching kernel from rpi, Then apply the patch.

[cosminbro]

Everything is ok now, except one thing.

I compile piCore 64 bit with kernel 6.1.25, and, when I try to install alsa.tcz, it get me an error:

Downloading: alsa-modules-6.1.25-rt11-piCore-v8.tcz
Connecting to repo.tinycorelinux.net (128.127.66.77:80)
wget: server returned error: HTTP/1.1 404 Not Found
md5sum: alsa-modules-6.1.25-rt11-piCore-v8.tcz.md5.txt: No such file or directory
Error on alsa-modules-6.1.25-rt11-piCore-v8.tcz

Of course, there is no file with such name. I unsquash the existing alsa-modules-6.1.25-piCore-v8.tcz and I modify the subfolder name from lib/modules to 6.1.25-rt11-piCore-v8.tcz

After reboot, ALSA still doesn't work....

[Rich]

Hi cosminbro
Reread the last post by Paul_123:

You are going to have to build the kernel and modules anyway.  Just pull the matching kernel from rpi, Then apply the patch.

[cosminbro]

I already rebuild the modules. I also rebuild alsa-modules-6.1.25-rt11-piCore-v8.tcz with drivers from new compiled modules one. Still ALSA doesn't work.

[Paul_123]

Did you build the kernel and modules -6.1.25-rt11-piCore-v8.gz. For the boot partition,   And then alsa-modules extension.

[cosminbro]

Did you build the kernel and modules -6.1.25-rt11-piCore-v8.gz. For the boot partition,   And then alsa-modules extension.

It's something strange here. I'm using config file 6.1.25-piCore-v8_.config.xz and the folder sound is included in generated modules. Isn't the same folder sound from inside the tcz alsa-modules extension?

[Rich]

Hi cosminbro
Is your new kernel finding the ALSA modules? If you run this:

Code: [Select]

modinfo soundcoreDoes it return information about soundcore.ko?
Do the  filename:  and  vermagic:  fields contain  6.1.25-rt11-piCore-v8 ?

[Paul_123]

That’s just packaging.   Modules in extensions are in /usr/local/lib/modules/xxxxxxxxx

There is a symlink in /lib/modules/ xxxxxx that points there.  If that link isn’t right, depmod won’t find the modules.   Your extensions can use the /lib/modules path.

[cosminbro]

I manage to get all work! Thanks.

Next, I want to repack the picore installation image with these modifications. How can I do this?