Newbie question about upgrading kernels

JasonMehmel · 2016-01-18 08:09:25

Hi all,

My media machine is running Mint 17, and I'd had some minor sound problems, mostly connected to HDMI as far as I could tell. (It wasn't hardware; everything worked perfectly when booting into Windows for games.)

But I'm not really asking about that problem. (Here's the link to where I do...)

When I was googling solutions, I came across one site that suggested going to the 4.x level of Linux Kernel, and it occurred to me that I don't know much about upgrading the kernel. Is that something that I should always wait to happen through the repositories? I'm guessing it would be dangerous to update it directly... but I'm not sure why.

If there's a newbie page I should have read for this answer, apologies in advance!

Head_on_a_Stick · 2016-01-18 08:13:53

I'm pretty sure Mint offers a selection of kernels to try.

Try:

apt-cache search linux-image

Different kernels are "safe" to install because you will have options in the GRUB menu to choose to boot into the old kernel if things don't work with the new one.

I'm on kernel 4.4 and its waaaaay better than 3.16 by this much *holds hands far apart* [/jk]

Mod Note: Moved to Help & Support (Other)

JasonMehmel · 2016-01-18 08:19:42

Would that same option work for BL? Because I might as well do both, if it's safe!

Head_on_a_Stick · 2016-01-18 08:26:07

JasonMehmel wrote:

Would that same option work for BL?

The BL option would be to use the newer kernel version from the jessie-backports repository:

sudo tee -a /etc/apt/sources.list <<< "deb http://httpredir.debian.org/debian jessie-backports main"
sudo apt update
sudo apt install linux-image-amd64/jessie-backports

JasonMehmel · 2016-01-18 17:18:52

So that's probably safe to do on BL?

I guess here's the core (kernel?) of the newbie question.

is it generally always safe to upgrade to the newest stable kernel? Is there a reason that this is something that has to be done outside of the automatic upgrades? What am I risking by doing the upgrade?

damo · 2016-01-18 18:01:07

JasonMehmel wrote:

...
is it generally always safe to upgrade to the newest stable kernel? Is there a reason that this is something that has to be done outside of the automatic upgrades? What am I risking by doing the upgrade?

I think for most people most of the time it is OK. Hardware sometimes needs a kernel downgrade. I'm running 4.3 on my BL laptop atm, and it is fine. And as already said, unless you edit your grub files the previous kernels will appear as a boot option, so upgrading the kernel isn't a one-way street.

The only reason I upgraded was to see if there was any difference using a new graphics tablet OOTB. There wasn't!

JasonMehmel · 2016-01-18 18:23:45

Cool. Thanks for chiming in on that.

What you were saying about hardware, is it that the newer kernel no longer has code for older hardware? Or just that the hardware can't take what the kernel is giving it?

damo · 2016-01-18 18:42:46

JasonMehmel wrote:

....
What you were saying about hardware, is it that the newer kernel no longer has code for older hardware? Or just that the hardware can't take what the kernel is giving it?

Sometimes

Head_on_a_Stick · 2016-01-18 19:08:12

JasonMehmel wrote:

That you were saying about hardware, is it that the newer kernel no longer has code for older hardware? Or just that the hardware can't take what the kernel is giving it?

It's called a kernel regression.

It happens when new features added to the kernel cause a bug with pre-existing hardware support.

Unfortunately, it occurs as a natural consequence of the rapid development pace of Linux and the only way to fix it is if users who suffer from regressions report them as bugs.

To get your regression fixed more quickly, perform a git bisect on the kernel to determine the dodgy commit that caused the regression and submit an appropriate patch.

This is why Debian stable sticks with the same kernel version and incorporates only security fixes and not new features.

hhh · 2016-01-18 23:49:50

https://wiki.debian.org/KernelFAQ

JasonMehmel · 2016-01-21 07:01:22

OK, so... funny story... I tried upgrading the kernel for my Mint installation, and it wouldn't recognize my keyboards, both a wireless and a wired USB. So I went back to the older kernel.

Here's a question; how can I undo this and remove the upgraded kernel? Is it as simple as an apt-get remove, and then another apt-update to bring everything else back in line?

My wife uses this machine a lot, and I want to keep her from having to pay attention to the Grub menu if at all possible.

Head_on_a_Stick · 2016-01-21 07:38:07

JasonMehmel wrote:

Here's a question; how can I undo this and remove the upgraded kernel? Is it as simple as an apt-get remove, and then another apt-update to bring everything else back in line?

Just `apt-get purge` should do it but make sure you get the package name right.

You can just leave the package installed and change the default GRUB menu entry number (they are counted from zero in GRUB) in /etc/default/grub and then run `update-grub`

See http://www.gnu.org/software/grub/manual … figuration (grub-mkconfig is run by `update-grub`)

JasonMehmel · 2016-01-21 07:52:10

Welp... I did the 'apt-get remove' option already; maybe I should have waited!

Is there anything left to purge?

Head_on_a_Stick · 2016-01-21 07:53:20

JasonMehmel wrote:

Is there anything left to purge?

I don't think so, I just use `purge` out of habit.

You may have /boot/config-`uname blah` or similar but it's not a very big file.

#1 2016-01-18 08:09:25

Newbie question about upgrading kernels

#2 2016-01-18 08:13:53

Re: Newbie question about upgrading kernels

#3 2016-01-18 08:19:42

Re: Newbie question about upgrading kernels

#4 2016-01-18 08:26:07

Re: Newbie question about upgrading kernels

#5 2016-01-18 17:18:52

Re: Newbie question about upgrading kernels

#6 2016-01-18 18:01:07

Re: Newbie question about upgrading kernels

#7 2016-01-18 18:23:45

Re: Newbie question about upgrading kernels

#8 2016-01-18 18:42:46

Re: Newbie question about upgrading kernels

#9 2016-01-18 19:08:12

Re: Newbie question about upgrading kernels

#10 2016-01-18 23:49:50

Re: Newbie question about upgrading kernels

#11 2016-01-21 07:01:22

Re: Newbie question about upgrading kernels

#12 2016-01-21 07:38:07

Re: Newbie question about upgrading kernels

#13 2016-01-21 07:52:10

Re: Newbie question about upgrading kernels

#14 2016-01-21 07:53:20

Re: Newbie question about upgrading kernels

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