What is the difference between an 'akmod' and a 'kmod'?

[Dead1nside]

I'm not an experienced user but it was my understanding that a kmod was a driver that needed to be inserted into the kernel or something to that effect. But now when I come back to Fedora 9 from Core 5 and 6 there seems to be these 'akmod' packages as well for traditional things like proprietary drivers and wireless drivers, particularly the madwifi driver in my instance.

I would appreciate it if someone could explain the difference between these two packages? A quick google suggested that it might have to do with not updating your packages if you update to a new kernel.

Thank-you in advance.

[bbfuller]

Hello Dead1nside

Your Google search provided the meat of the answer.

On this machine for instance I've just installed the nvidia graphics drivers.

I had a choice. If I installed the kmod-nvidia package and its associated dependencies, each time the kernel was updated I wouldneed to download a new kmod package.

If you install akmod-nvidia and its dependencies it should be a one off job, each time you update your kernel and reboot the machine akmod will generate the new packages needed for the new kernel.

On a fast internet connection I doubt there is much in it, on a slow connection it could well be worthwhile, though I believe you need kernel-devel for it to work which in itself is a sizeable download.

There is one other scenario and that is where you keep multiple kernels but only install the nvidia drivers during the life of the distribution. Previously it may have been difficult to get kmod-nvidia's for the earlier kernels but with akmod it should generate the required parts as soon as you boot the older kernel.

That of course applies to all the akmods, not just nvidia.

EDIT:

There used to be a similar (and still maybe) service from the 'freshrpms' repository, only there they called it dkms-nvidia, where dkms stood for 'dynamic kernel module support'.

[Dead1nside]

Ah thank-you very much bbfuller. dkms looks familiar to my eye also.

Would dependency resolution not update any kmods when there is a kernel update though? I had my madwifi drivers for my old kernel, seemingly become joined by the current madwifi drivers for the new kernel that was released today.

Either way I'll try the akmod next time, certainly sounds a lot better than the old situation, things just wouldn't work after a kernel update, at least for me. But maybe I was doing something wrong.

Thanks.

[bbfuller]

Hello Dead1nside

Would dependency resolution not update any kmods when there is a kernel update though? I had my madwifi drivers for my old kernel, seemingly become joined by the current madwifi drivers for the new kernel that was released today.

Yes, usually it would. There have been instances in the past though where there has been a day or two's delay in getting out the Livna updates to match a new kernel and akmod would overcome that.

I assume as well that if we could all be persuaded to move over to the akmod system it would be one less set of packages to recompile whenever a new kernel was issued.

[Dead1nside]

The reason that madwifi updated along with my new kernel appears to be a 'metapackage' as it calls itself called madwifi-versionnumberhere.lvn.fc9 .

Just adding it here for posterity. Thanks again for explaining things bbfuller.

[sidebrnz]

Currently I'm using kmod because that's how the instructions I found here were set. Is there any reason to switch to akmod and if so, what's the best way to do it?

[Firewing1]

You can use both together:

yum install kmod-foo akmod-foo

If kmod-foo isn't out when the new kernel is, reboot and akmod will take care of it for you.
Firewing1

[Dead1nside]

There's a good article on fedorasolved.org about this: http://fedorasolved.org/Members/zcat/akmods

[sidebrnz]

I followed the instructions, but ran into a problem. When I had akmod try to rebuild the kmod, it failed because the appropriate devels were missing. Checking with yumex, I found that there was a new kernel and kmod available, so I installed them as well as the kernel headers and rebooted. All is OK now, but what devel files do I need to make sure it works next time?

[leadgolem]

Probably "kernel-devel" and/or "kernel-headers".

[sidebrnz]

I didn't see kernel-devel in yumex, but might not have looked properly. Checking with youm, there's kernel-devel.i586 and I'm now installing it Just In Case.

[Hlingler]

I didn't see kernel-devel in yumex, but might not have looked properly. Checking with youm, there's kernel-devel.i586 and I'm now installing it Just In Case.

"i586" ? I don't think that's a good idea unless you really, actually have an i586 kernel installed and running... you want the i686 kernel-devel packages that match the installed kernels.

V

[bbfuller]

Hello sidebrnz

You really shouldn't just install kernel-devel without checking what you need.

The command:

uname -a

in a terminal will tell you that.

On this machine for instance it reports:

[bbfuller@atx17 Desktop]$ uname -a
Linux atx17.local 2.6.25.6-27.fc8 #1 SMP Fri Jun 13 16:38:52 EDT 2008 i686 athlon i386 GNU/Linux

I've highlighted in red where it shows the architecture of the kernel on this machine. So I would be looking for the kernel-devel package that matched "2.6.25.6-27.fc8" and "i686". I'd be surprised if you had i586.

The thing is then, that once you have a kernel and it's matching devel package installed, using yum to do updates should update the kernel and its associated devel package.

I would have thought that if you installed akmod-ndiswrapper it would have installed the kernel-devel package as a dependency. Depending on how you are looking for it the kernel-devel package may not be "available for you to install because it already is.

Don't get into the situation where you have kernel-devel i586 and i686 on the same machine. It's unecessary, it's also probably dangerous.

rpm -q kernel-devel

will tell you just what you already have.

[sidebrnz]

Thanx for the advice. I'll get the right one installed. Why, however, would I have installed akmod-ndiswrapper when I only need akmond-nvidia?

Checking, I have the i686 installed, not the i586. All's swell that ends swell, as Cutie Bunny used to say.

[bbfuller]

Hello sidebrnz

Why, however, would I have installed akmod-ndiswrapper when I only need akmond-nvidia?

No reason at all as far as I can see. This thread has been using nvidia as an example but there are several other packages out there that work on the akmod principle. Maybe you just clicked on the wrong one?

It shouldn't do any harm installed in any case.