Remaining printk miscellany
By now, you're familiar with most of the typical and pragmatic means to leverage the kernel's powerful and ubiquitous printk and its related APIs, macros, and frameworks. Of course, innovation never stops (especially in the open source universe). The community has come up with more and more ways (and tooling) to use this simple and powerful tool. Without claiming to cover absolutely everything, here's what I think is the remaining and relevant tooling to do with the printk that we haven't had a chance to cover until now. Do check it out – it will probably turn out to be useful one day!
Printing before console init – the early printk
You understand that the printk output can be sent to the console device of course (we covered this in the Understanding where the printk output goes section(see Table 3.1). By default, on most systems, it's configured such that all printk messages of log level 3 and below (<4)...
