Booting Linux Fast & Fancy
Booting Linux is a topic which seems to be solved since 1992. And even very recent articles  and videos  on the web let us suggest that people have been there, done that and nothing is left any more to the casual observer. Wait... really? Our experience in the Pengutronix lab seems to be different. Most Embedded Linux Systems we get our hands on have several problems during their boot stage:
Flicker. You switch the box on, the backlight blinks. Sometimes you see stripes, blinking colors. Then the BIOS starts up, boots Grub or an other bootloader, with a text mode screen. Another flicker. The kernel boots, starts the framebuffer (flicker), then userspace takes over, x.org starts (flicker) and the graphical application starts up.
Long delays. It still takes very, very long until the application has full control over the system. We have seen embedded systems which need more than 1.5 minutes from power-on to the application, and even with applying "normal" magic to the systems, 30...45 s are still quite usual.
So what's the real state of the union? This article is an attempt to find it out.
Our Test Setup
In order to check what's possible with recent Linux systems, we built up a system based on