Kernel customization: What should be modules and built-in?
 

Hello,

I'm compiling a custom kernel for my laptop but isn't it a bad idea to build in everything I regularly use (gpu, wireless, filesystems etc.)?

What would you advise?

Hi,

It is up to you to decide what to use (there might be one or 2 exceptions).

I like my kernels as lean and static as possible. The only thing that is not static in my setup (one of the exceptions): Alsa This is due to the fact that software that uses alsa looks specifically for a module. This might change in the future and if it does I'll switch to a static entry.

Using modules might also mean that you need to add to/edit your initrd file to make sure the module is available during boot.

My advise would be: Build as static as possible (but that is a personal opinion).

Hope this helps.

Thanks for your answer. I have already disabled unnecessary gpu and wlan drivers and will disable ethernet too (no ethernet on laptop). What would make the biggest difference (performance-wise and kernel size-wise) to disable? Suggestions are welcome.

Hi,

A kernel that is configured to only use what you need/want is the best. Telling you which options to enable/disable is hardly doable without knowing the hardware details of your setup, I can however give you some general information on how to make you kernel mean and lean:

- Check your hardware and only enable that what you have. Use tools like lspci, lshal, dmesg and manuals (etc) to determine your hardware. Example: If you have an intel based machine disable the amd specific stuff (or vice versa).

- Only enable laptop specific entries that are relevant for your specific laptop.

- Ask yourself which filesystem(s) you want to use (on your laptop and which you might need to mount from an external source): Disable all others (do you actually need ntfs, reiserfs, xfs, btrfs, etc).

- Initially disable deprecated options.

In general I would advise you to check all the options. Sometimes the help tab will help you in deciding.

BTW: Do make sure you have a fall-back option, disabling an option that you do need might make your system unresponsive!

Hope this helps.

It was very helpful, thanks. My MacBook Air loads the joydev module in the stock kernel, but it seems to be for joysticks and I don't have any.

Hi,

If you have an apple, do have a look at the apple specific entries that are present. These I know of:

- Device Drivers -> Graphics support -> Backlight & LCD device support -> Apple Backlight Driver
- Device Drivers -> Input device support -> Mice -> Apple USB xyz
- Device Drivers -> Macintosh device drivers

There might be more.

Do check first if you actually need them!

BTW: You're welcome :)