Okay, now that you actually have been convinced to try the 2.5 Linux kernel (see previous article), how can you test this kernel out. And, what should you do if you have any problems?

First off, before you configure the 2.5 kernel--say, while you are downloading it--go read Dave Jones's excellent "What to Expect from 2.5" document. In that document, pay specific attention to the sections covering the Input Layer, the Framebuffer layer and module information. These sections of the kernel configuration process are the most confusing for newcomers to the 2.5 series. If you don't pay attention, it is very easy to end up with a kernel that either displays nothing on the screen or doesn't accept any input from the keyboard.

After configuring the kernel with the specific hardware you have on your system, build the kernel, install it and reboot. Don't select all the drivers, here; a number of them do not compile because no one seems to have hardware for them anymore. If you've never done this build and install process before, I suggest you read the Linux Kernel HOWTO, which details all of the necessary steps involved. I also do not recommend that 2.5 be the first kernel you ever build on your own. Try the 2.4 kernel first to rule out any operator errors you might come across.

If you do have hardware for a driver that does not build, please report this. Most kernel developers do not have access to a wide range of hardware, so they are apprehensive about fixing drivers they cannot test. If you post your building problem to the linux-kernel or kernel-janitor's mailing list, and if you have the hardware for the driver and are willing to test patches, you should be able to find a willing developer to provide you with updated code.

Now that your 2.5 kernel is up and running, what should you do to test it? It's simple; do the normal tasks you always do on your 2.4 or 2.2 kernels: run X, browse the Web, read e-mail, play games, write documentation, write code and so forth. Every user stresses the operating system in different ways; therefore, there is no one, correct way to test.

If you think you've found a problem, first off, search the past week or so of the linux-kernel mailing list to see if others have had the same problem; a fix already may have been posted. If you do not see anything relevant, try searching the 2.5 kernel bug database for your specific issue. If you still cannot find anything relevant, please create a new bug in the database so the kernel developers can realize there is a problem. From there, the bug will be assigned to someone to look at, and more importantly, it can be found by others having the same problem in the future.

I hope this short mini-article helps people start testing out the 2.5 kernel. Without users testing, there is no way that the kernel can become stable enough for everyone to use in the future.

Greg Kroah-Hartman is currently the Linux USB and PCI Hot Plug kernel maintainer. He works for IBM, doing various Linux kernel-related things.