Kernel debs?

[andypugh]

Does the repo build working kernel debs?

Having found that our existing 4.19.y-rt24 kernel would not work with the latest crop of Pi4s I have patched 5.4.83 with the rt48 patch. This is working fine on my Pi400, but if I build debian packages and install the linux-image deb on a stock pi SD card image I get a non-booting system.

I am wondering if any of the changes that you have made in this repo post the RT patch are relevant to deb packaging?

[kdoren]

I haven't made any changes post rt-patch except to fix the kernel .config used to build (my first try I got it wrong).

I haven't tried packaging it as a deb. In theory I could do it (I have an apt repo) but it hasn't been a priority. Also, I'm not sure where to find the deb packaging files (I'd rather not try to re-create them). This post is not encouraging: https://www.raspberrypi.org/forums/viewtopic.php?t=265774

The kernel files here should work in a deb though (just not on a RPi3, not sure why).

The advantage to having a deb package in a repo is that it would make it easier to do updates.

I have been installing by copying the files into /boot/rt and /boot/rt/overlays, then setting config.txt to use it.
process is here: https://github.com/kdoren/jambox-pi-gen/blob/jambox/stage3/05-install-rt-kernel/00-run.sh

This makes it easy to switch kernels for comparison testing.

[kdoren]

@andypugh I should have looked harder, the scripts for making a deb package are there in the linux repo under the scripts directory, I presume that's how you built yours. I haven't tried running them yet, I'll give that try when I have time.

[andypugh]

Indeed.
make deb-pkg
Will create a kernel deb, which can be installed with apt-get or dpkg on a stock install, and will (probably) change the kernel.
I have made debs using my own patched Pi kernel repo:
https://github.com/LinuxCNC/raspberrypi-linux
But the resulting deb package: http://www.linuxcnc.org/temp/linux-image-5.4.83-rt48-v7l+_5.4.83-rt48-v7l+-4_armhf.deb is only partially successful at making a working system. There seems to be a problem with memory > 3072MB preventing USB from working.
Though all my testing of that aspect of that has been on our 4.19 realtime kernel with the USB eeprom patch backported to it.
I was wondering if you had done any work on the deb packaging scripts to improve applicability to the new hardware levels, but it sounds like you haven't.

[kdoren]

@andypugh deb package should be installing the same binaries in the same places. If it works OK with manual install but not with deb install, that seems odd. The deb package scripts do look like they need some environment vars set.

Only issue I have found is that it won't boot on a Pi3, not sure why. But Pi4 is working just fine, no problems with USB on 4GB units. In fact USB problems with 4.19y rt kernel are what motivated me to build my own.

I do use 64-bit kernel, I can't see a reason to use 32-bit. 64-bit kernel runs just fine under the standard 32-bit OS. However I did build a 32-bit kernel from same sources and it worked also.

In my notes under "Releases" I show the exact commands I used to patch the sources. I started with the exact commit "Merge remote tracking branch" by popcornmix, and since the closest patch set available was 1 tick ahead, I verified that the patch set did not try to patch any files that had been changed subsequently. Maybe I just got lucky.

[kdoren]

@andypugh I built a 5.10.16 32-bit PREEMPT_RT kernel, it's posted in releases. I also posted the deb packages but I haven't tried installing from them.

[kdoren]

@andypugh I updated the instructions for installing kernel from deb package (my original instructions would boot but had issues). Installing from deb packages is now my preferred method, it's simpler and I can put them in my apt repo.