[stevekemp]

I've never written a driver myself, because all my hardware is supported. But I've certainly added new PCI IDs to existing drivers, and done that kind of low-level learning.

I expect if I found a random piece of hardware that was close to an existing one that adding the driver, or updating things so that it worked on the new hardware would be possible. It's just not a situation I've come across.

What I found useful/educational was writing a simple linux security module.

1. LSMs are essentially isolated. 2. They don't care about hardware. 3. You can do lots of things with them. Even horrid evils things.

For example I put together the following module in which the kernel calls back to userspace every single time you execute a binary, to decide whether it should be permitted or not:

https://github.com/skx/linux-security-modules

(And yes, I appreciate that is almost exactly as horrid as it sounds! So much fun to hack around with though.)

[lewis1028282]

You can just write char drivers that operate a slab of kernel memory, and implement all the syscalls like open, read, write on that piece of memory.