[solved] New kernel does not boot

majoron · Last edited by majoron on Wed Nov 14, 2018 11:56 am; edited 1 time in total

Hi,
I have a new PC and I'm having troubles to find a proper kernel config: the kernel does not boot. But I don't know why. It only powers off the computer. There must be some options that prevent the kernel from even being loaded, but no idea of what can it be.

I have tried to run the kernel with kexec, but the kernel provided by the Gentoo installation CD does not allow me to run kexec

Any ideas?

BR
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NeddySeagoon · Posted: Mon Nov 12, 2018 3:10 pm Post subject:

majoron,

Please start with SystemRescueCD. Its Gentoo based.
Either on a CD or a USB stick.

Is this a computer you assembled yourself?
Has it ever done anything except power off ?
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NeddySeagoon

Computer users fall into two groups:-
those that do backups
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Cuong Nguyen · Apprentice Joined: 18 Jan 2018 Posts: 152

NeddySeagon,

Is it OK to build new kernel and initramfs with genkernel --all-ramdisk-modules --firmware to make sure vmlinuz will load any modules that not binary compiled into the kernel?

NeddySeagoon · Posted: Mon Nov 12, 2018 4:24 pm Post subject:

Cuong Nguyen,

Yes.

You will get a big bloated initrd but that won't matter.

genkernel does not build every module in the kernel. It has its own .config file that it uses.
I don't know if it supports NVMe yet, so NVMe users should use the --menuconfig option to check.
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Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

Cuong Nguyen · Apprentice Joined: 18 Jan 2018 Posts: 152

NeddySeagoon · Posted: Mon Nov 12, 2018 7:42 pm Post subject:

Cuong Nguyen,

My rules of thumb are to build everything needed to boot, into the kernel.
That way, either no initrd is required, or if you need user space tools to a assemble raid and start LVM, like I do, the initrd does not contain any kernel modules.
That means that the initrd need not be rebuilt for kernel updates. Its just like firmware.

Next everything needed after boot should be a loadable module. This isn't hard and fast.
e.g. I could make amdgpu as a module but I like an early console, so I have amdgpu and its 20 firmware files built into the kernel.

Anything you always use can be built in too, even things you load with module parameters.
Module parameters can be passed on the kernel command line. Modules are much better than built in for parameter trial and error.

Lastly, things you won't need, turn off. Good use of the menu system in the kernel config tools will save a lot of time.
When you turn off a menu, the options on that menu assume sensible default values, usually off.
The example here is if you don't have a TV Tuner, turn the menu off. Don't read all the options and turn them off one by one.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

Cuong Nguyen · Apprentice Joined: 18 Jan 2018 Posts: 152

NeddySeagoon · Posted: Tue Nov 13, 2018 10:56 am Post subject:

Cuong Nguyen,

See kernel seeds for the method and Pappy's preconfigs! for more up to date 'seed' .config files.
The first link is unmaintained but the method is still good.

Keep several kernels, everyone make one that won't boot sometime and its easier go use the grub menu to fix things than find your boot media and do the mounts and chroot.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

majoron · Posted: Wed Nov 14, 2018 11:55 am Post subject: