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andypugh wrote:

Does the machine still boot with the earlier kernel selected?
What was that kernel?

I want to say I didn't even see options for the old kernel. I'll report back on this asap.

andypugh wrote:

Have you tried running a pre-compiled kernel package?
Does Mint find any such realtime kernels in the package manager? If not then you could try adding the debian 9 repositories to see what you can find.

Honestly I didn't even think to look in the repos for a precompiled kernel. It didn't occur to me that would be an option. Does anyone happen to know if the rt-preempt kernel is available in the mint 19.1 repos? If I can quickly get this install repaired I'll look for it, otherwise I'll just go back to a linuxcnc iso.

andypugh wrote:

The kernel panic hints that something went wrong during your kernel compile.
Out of interest, how long did you have to wait after the "make" command, and were there any error messages generated?

I don't know. From previous experience I didn't bother waiting around to find out. I went to bed and when I came back there were no error messages on the terminal at that time.

I feel like you've asked lots of good questions and I've had zero helpful answers. I'll explore grub more thoroughly and see if another kernel will load and report back.

Linuxmint 19.1 when compiling now compiles and installs all modules and keeps symbols making the image way too big so it cant boot.

You have to strip the symbols and compile it so just the modules required. check the image compared to the original, it will probably be like 10 times bigger.

I tried all kinds of stuff to fix it and couldn't get it to compile small enough.

So I installed debian 9. it has preempt RT kernel in the repo. But this has watchdog reboot issue.

Would be nice and very appreciative if some kernel guru on here and help us on how to configure so the kernel is a decent size so grub will load it.

bevins wrote:

Linuxmint 19.1 when compiling now compiles and installs all modules and keeps symbols making the image way too big so it cant boot.

You have to strip the symbols and compile it so just the modules required. check the image compared to the original, it will probably be like 10 times bigger.

I tried all kinds of stuff to fix it and couldn't get it to compile small enough.

So I installed debian 9. it has preempt RT kernel in the repo.

I'm curious, did you try to install the preempt kernel from the debian repo into your mint installation? I gather that was what andypugh was suggesting here "Does Mint find any such realtime kernels in the package manager? If not then you could try adding the debian 9 repositories to see what you can find."

AgentWD40 wrote:

bevins wrote:

Linuxmint 19.1 when compiling now compiles and installs all modules and keeps symbols making the image way too big so it cant boot.

You have to strip the symbols and compile it so just the modules required. check the image compared to the original, it will probably be like 10 times bigger.

I tried all kinds of stuff to fix it and couldn't get it to compile small enough.

So I installed debian 9. it has preempt RT kernel in the repo.

I'm curious, did you try to install the preempt kernel from the debian repo into your mint installation? I gather that was what andypugh was suggesting here "Does Mint find any such realtime kernels in the package manager? If not then you could try adding the debian 9 repositories to see what you can find."

I didn't try that, I needed to get a system up and running. I may try adding debian repo to linux mint, I'm not sure how well that will work though.

This should strip the symbols and create an imagel small enough to be usable.

andypugh wrote:

It seems like this should be a config option. "Enable loadable Module Support" or similar?

Its loading the modules. its loading all the modules and all the symbols for developers. This is my take on it.

When I have a few hours, I will try stripping them with that command and see if it works.

Newer kernels that I have built have huge initrd images (nearly 400 mb)
but the zipped kernel size is still about 8M max which does not
seem to cause an issue. Is it possible that you have a separate /boot partition
that is out of space?

PCW wrote:

Newer kernels that I have built have huge initrd images (nearly 400 mb)
but the zipped kernel size is still about 8M max which does not
seem to cause an issue. Is it possible that you have a separate /boot partition
that is out of space?

I manually configured my partitions at setup but didn't create a separate boot partition. /boot lives on the main partition.

I've just installed Mint 19.1 on a virtual machine, added the debian stretch repo, and installed debian's rt kernel. After some finangling in the grub customizer I've successfully loaded mint 19.1 with the 4.9.0-9-rt-amd64 kernel as confimred by uname -a.

Of course it's untested, just wanted to let you all know.

Is the 4.9 kernel suitable? John's instructions are for the 4.19 kernel.

And to answer a previous question from andy, the default kernel right now on mint 19.1 appears to be 4.15. Rather, that's what's included on a fresh install. I hadn't bothered with apt-get upgrade yet.