Understanding /boot/config file

Question

In /boot/config-$kernel_version I see things like:

CONFIG_X86_TSC=y
CONFIG_CAN_TSCAN1=m

Now, I thought that y stood for yes, which means the option is set. But how about m?

Answer 1

Y = Module is compiled directly in kernel. 

Notes: Some drivers should be ready all the time in kernel functionality, without them system can't function like Unix domain sockets (CONFIG_UNIX) which should be Y

N = Don't compile module in kernel. do nothing. 

Notes: Its your choice whether you want it or not.

M = Compile module as loadable module. Kernel will load this module On **Demand**. 

Notes: M means loadable module which they don't need to stay up all the time, Like Sound Driver which you can load when you want to play music. It will make your system more efficient.

Answer 2

It means it is compiled as a kernel Module.

• 'N' - means it is not compiled at all;
• 'Y' - means it is compiled inside the kernel binary file;
• 'M' - means it is compiled as a kernel module.