[elrepo-devel] real kmod versions

[Phil Perry]

On 06/10/11 13:49, Farkas Levente wrote:
> hi,
> how can i know which is the real version of a kmod in elrepo? eg there
> is a coretemp-kmod-1.1-9 in elrepo. is it newer then the latest kernel
> in rhel-5.7? there is page:
> http://elrepo.org/tiki/kmod-coretemp
> which said it's newer then in 5.4, but what about 5.7? i also look into
> the source but that's do not help me a lot:-(
> and the same apply to w83627ehf, w83627hf, it87 etc....
> it's be nice to keep and up-to-date table about rhel-5.x version and
> elrepo kmod version comparision.
> regards.
>

There is a page here:

http://elrepo.org/tiki/Driver+Versions

but I'm afraid it's not very up to date, at least for the drivers you 
mention above. But it's a Wiki, so if anyone wants to maintain it, 
please ask and you will be granted the necessary permissions.

For drivers versions backported in the kernel, it's difficult. For 
example, most (maybe all) of the drivers you list above have no internal 
version number associated with them in the kernel so it's not a trivial 
task to track them or know which kernel RH backported them from, other 
than examining the source code to see which patches have been 
backported. As for our kmod packages, I always update the changelog to 
show the latest patches and/or which kernel the driver was backported 
from, so that should be considered the definitive source of information. 
Our package version numbers are largely meaningless (at least for 
backported kernel drivers), other than where an internal version number 
does exist and then we will use it.

For example:

$ rpm -q --changelog kmod-coretemp

* Sat Feb 19 2011 Philip J Perry <phil at elrepo.org> - 1.1-9.el5.elrepo
- Backported from kernel-2.6.37.1
- kABI compatible with kernel >= 2.6.18-238.el5
- No longer compatible with xen kernels
- Include patches through [2010-10-25]
- Revert "fix initialization of coretemp" [2010-09-24]
- Revert "register alternate sibling upon CPU removal" [2010-09-24]


$ rpm -q --changelog kmod-it87

* Sun Aug 07 2011 Philip J Perry <phil at elrepo.org> - 1.1-9.el5.elrepo
- add the docs.
- Rebase to kernel-2.6.39.4
- Fix label group removal [2011-08-03]
- Use pr_fmt and pr_<level> [2011-01-12]


For the backported modules I currently maintain (coretemp, it87, 
k10temp, w83627ehf, w83627hf, f71882fg, joydev, thinkpad_acpi, udlfb), I 
try to check for new patches for each new kernel release. That said, it 
is getting harder to backport patches for each new kernel release, 
particularly on RHEL5. For example, many new patches in kernel-3.0 
failed for coretemp and it87 so for those drivers it might be a case 
that we continue to backport patches from 2.6.39.x so long as they build 
but recognise we are nearing the end of the road for supporting some 
drivers.

Generally, our drivers are newer than those currently available in RHEL 
and we will continue to provide and update them for as long as there's a 
need. As always, if the RHEL kernel driver works for you then you should 
use that. When RHEL drivers catch up or become newer and we no longer 
wish to maintain the driver in elrepo, we will deprecate our kmod 
package in favour of the distro kernel driver. For example, we recently 
did this with kmod-sata_via when the native kernel driver in RHEL-6.1 
contained the backported fix that was addressed in our kmod release.

So the bottom line is that it's not easy to do any direct comparisons, 
especially for native kernel drivers - the changelog will tell you which 
kernel the elrepo driver is backported from but it's not so easy to 
determine that information for the kernel driver unless you're tracking 
the source code. What I can tell you for the hwmon drivers that you list 
above is that Red Hat did a large backport of the /hwmon branch in the 
RHEL-5.5 release and, looking back at my notes from my testing of the 
5.5-beta release, the code seemed to have been backported from 
~kernel-2.6.26 released somewhere around August 2008. I don't think 
those drivers have had a significant update since although the odd 
individual patch may have slipped through.

For many vendor drivers that are also in the kernel, such as the Intel 
nic drivers that Alan maintains for example, it's a lot easier because 
the vendor's driver version numbers are used. There we can see (from the 
Wiki page above, or from modinfo) that the Intel e1000e driver is 
currently at version 1.6.2 in elrepo, 1.3.10 in RHEL5 and 1.2.20 in 
RHEL6 so it's really easy to make direct comparisons (bet you weren't 
expecting to see newer drivers in the RHEL5 kernel than the RHEL6 kernel).

Regards,

Phil