title: Painless kernel mods with ELRepo link: https://onemoretech.wordpress.com/2009/10/29/painless-kernel-mods-with-elrepo/ author: lembobro description: post_id: 221 created: 2009/10/29 15:36:45 created_gmt: 2009/10/29 15:36:45 comment_status: open post_name: painless-kernel-mods-with-elrepo status: publish post_type: post

Painless kernel mods with ELRepo

Here’s something to give a try if you’ve got a test box sitting around just begging for something to do.

First off, let me make clear that my only connection to the ELRepo yum repository is as a grateful user. ELRepo is, in the words of the main page:

a RPM repository for Enterprise Linux packages. ELRepo supports Red Hat Enterprise Linux and its derivatives (CentOS, Scientific Linux and others).

ELRepo currently focuses on hardware related packages to boost your experience with Enterprise Linux, this includes filesystem drivers, network drivers, webcams and video drivers.

During some (still inconclusive) testing of a failed firewire (IEEE1394) connection using the CentOS Plus version of the latest kernel for RHEL, I decided to give the relatively new ELRepo a try.

The packages available from the repo leverage one of the main design advantages of the Linux kernel, the fact that hardware drivers can be installed and loaded as modules without necessitating a complete recompile of the kernel. An extension of this is to use the “kABI tracking kmod” feature in RHEL to obviate the need to recompile driver modules on every kernel update (which are quite frequent, even for the very stable RHEL product). As explained in the ELRepo FAQ:

Linux drivers must be built against the kernel for which they are to be used. As most drivers are part of the kernel, this normally isn’t a problem. However, when using 3rd party drivers, the driver must be recompiled against each new kernel. This causes inconvenience for users who must rebuild the driver against each new kernel update. A kABI-tracking kmod is a kernel module (driver) that is compatible with any given kernel Application Binary Interface. A consistent kABI is a key feature of an Enterprise Linux distribution and, so long as upstream doesn’t break the kABI, a kABI-tracking kmod driver will work across all kernels for a given Enterprise Linux distribution (eg, RHEL-5, CentOS-5, Scientific Linux 5) without the need to recompile the driver for each kernel update.

In my case the commercial nvidia drivers I need to allow VMware and other applications to make the most of my add-on graphics cards are now available from ELRepo as kABI packages. The required packages for the latest CentOS 5.4 kernel are:

kmod-nvidia-185.18.36-2.el5.elrepo nvidia-x11-drv-185.18.36-2.el5.elrepo

In addition to the nvidia card, I also chose to install the following package to IEEE1394 (Firewire) support, which I used to rely on the CentOS Plus kernel for:

kmod-ieee1394-1.0.0-3.el5.elrepo

Thus far, this hasn’t helped me to get dvgrab working with my firewire-equipped minicam any more than the CentOS Plus kernel, but I’m hopeful a little more time invested in debugging (and search bug reports) will pay off.

Copyright 2004-2019 Phil Lembo