noob updating kernel [solved]

while true · Posted: Sat Nov 02, 2019 10:57 am Post subject: noob updating kernel [solved]

Hello Gentoo people,

since i learned to upgrade kernel, it is quite a chour/task to set new kernel up.
for me it takes time since i tend to measure twice and than start up the chain saw.
upgrading kernel is nice, but there is update like every week...

so i skipped updating kernel for a while,
my last saved config is: kernel-config-5.2.8-gentoo
my umane -a says: Linux keeshta 5.2.11-gentoo #1 SMP Sun Sep 1 01:17:33 CEST 2019 x86_64 AMD FX(tm)-8350 Eight-Core Processor AuthenticAMD GNU/Linux
and

fturco · Veteran Joined: 08 Dec 2010 Posts: 1184 Location: Italy

I'm not sure I understood correctly, but if you have a working kernel configuration in ~/kernel-config-5.2.8-gentoo, you can copy it to /usr/src/linux/.config and then run make olddefconfig. Of course first make sure you updated the symlink to the desired kernel version.

NeddySeagoon · Posted: Sat Nov 02, 2019 12:15 pm Post subject:

while true,

Unless you have very new hardware, you don't need every kernel update.
e.g. moving from 5.2.8 to 5.2.9 is a bugfix. If you have kernel issues, do it, if not its fine to leave.

Do update from 5.2.x to 5.3.y or after a few versions, the questions that make oldconfig asks appear never ending.
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Jaglover · Posted: Sat Nov 02, 2019 12:47 pm Post subject:

fturco · Veteran Joined: 08 Dec 2010 Posts: 1184 Location: Italy

Jaglover: can you explain me what's wrong with make olddefconfig, please?

kajzer · l33t Joined: 27 Nov 2014 Posts: 897

Should be oldconfig , not olddefconfig.

fturco · Veteran Joined: 08 Dec 2010 Posts: 1184 Location: Italy

From make help:

oldconfig: Update current config utilising a provided .config as base
olddefconfig: Same as oldconfig but sets new symbols to their default value without prompting

As far as I know, in both cases old kernel options are not going to be changed in any way. That's the most important thing in my opinion.
But personally I don't like to make an explicit choice for every new kernel option, for every new kernel version. So that's why I choose olddefconfig. I don't see anything wrong with that.

fturco · Veteran Joined: 08 Dec 2010 Posts: 1184 Location: Italy

Jaglover · Posted: Sat Nov 02, 2019 2:06 pm Post subject:

You are running Gentoo. I assume you know why you chose it. Most people do it because Gentoo gives you choices. Choices only you can make, choices which suit your needs.
Modern Linux kernel is no different. You have to make choices. By running 'make olddefconfig' you apply someone else's choices. Every time I run 'make oldconfig' and there has been a mayor version upgrade I have to correct many options, default choices made by kernel developers are not best for my use case.
There seems to be a belief [among lazy or noobs] kernel configuration can be automated. If you get a little deeper into this you will understand it cannot be automated. Maybe in the future, when everyone has a chip installed in their brain and there is a device which communicates with it and interacts with kernel configuration process. :wink:

Being lazy and doing 'make olddefconfig' is OK if you do it knowingly to your own computer. Telling to someone else to do it without warning it will lead to suboptimal configuration is not OK.
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fturco · Veteran Joined: 08 Dec 2010 Posts: 1184 Location: Italy

I think it really depends on who you are saying that to. A beginner who has not much experience building kernels may be perfectly fine with olddefconfig, even if he's running Gentoo. After all, his computer won't explode when booting a slightly bigger kernel! After he becomes more experienced, he may indeed find oldconfig more appropriate and enjoy working on minimizing kernel size.

while true · Posted: Sat Nov 02, 2019 3:24 pm Post subject:

i just took dogs for a walk...

cia fturco,

ok, so i need to get over that first step,
that is why i am here,
where do i copy it from? from here?
keeshta /usr/src # ls linux-5.2.11-gentoo/.config (tab tab)
.config .config.old
i also have
ls /boot/config*
config-5.2.11-gentoo

can i skip this first step since i have 5.2.11.config in 2 places and try to continue to upgrade my kernel?

and bonus question, in /usr/src/ i have like over 40 linus* folders, can i simply delete them and leave last two?

what do you have in that jag Jaglover? so i am noob, but i see other distros, well i use two others (love my RPi's), do not have this freedom of choice to build kernel, well they do, probably compile kernel like we do, but kernel upgrade usualy is taken care of during usual update. we take more steps, i do not mind, but i am stuck and appritiate helping hand.

Jaglover, why did my usual kernel upgrade stopped at first step?
# cp /usr/src/linux/.config ~/kernel-config-`uname -r`
cp: cannot stat '/usr/src/linux/.config': No such file or directory

and, Jaglover, can i do without it, and try to procceede with next steps?

now that would teach the noob a thing or two!

Thank you all, Neddy that means you too

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fturco · Veteran Joined: 08 Dec 2010 Posts: 1184 Location: Italy

I would first check if your /boot/config-5.2.11-gentoo is identical to /usr/src/linux-5.2.11-gentoo/.config with:

NeddySeagoon · Posted: Sat Nov 02, 2019 6:07 pm Post subject:

fturco,

I would add one step before deleting anything.

After the reboot into the new kernel, check the date and time in the output of

fturco · Veteran Joined: 08 Dec 2010 Posts: 1184 Location: Italy

Thanks NeddySeagoon, I added your tip to my previous post.

charles17 · Advocate Joined: 02 Mar 2008 Posts: 3613

while true · Posted: Sun Nov 03, 2019 4:18 pm Post subject:

fturco