[HOWTO] Silent boot and shutdown (with splash)

[Jari_42]

It took me quite a while to figure out how to get an (almost) completely silent boot and shutdown with flicker-free splash on gentoo, so I thought I'd share it here (constructive comments and suggestions welcome):

1. Silence GRUB2
   By default GRUB2 is annoyingly verbose, however you can patch the GRUB2 sources to silence it:
   https://bbs.archlinux.org/viewtopic.php?id=209207
   recompile and then reinstall the silenced GRUB2 to the MBR:
   https://wiki.gentoo.org/wiki/GRUB2#Installing_the_boot_loader
   By far the easiest way to do this is to create a local portage overlay with a patched GRUB2.
   
   This still leaves an annoying flashing cursor before GRUB2 starts but apparently this requires adding a custom interrupt handler in assembler which is beyond me (any help appreciated):
   https://unix.stackexchange.com/questions/381076/how-to-hide-grub-2-cursor-before-kernel-splashscreen-menu
   
   
2. Silence Kernel
   To disable kernel decompression messages, make sure that you add 'quiet' to the GRUB2 kernel command line options:
   https://wiki.gentoo.org/wiki/GRUB2_Quick_Start#Silent_kernel_decompression
   Also add vt.global_cursor_default=0 to the kernel command line parameters to hide the blinking console cursor.
   
   
3. Use Kernel Mode Setting
   This is needed for a flicker-free splash, enable it as follows:
   https://wiki.gentoo.org/wiki/Xorg/Guide#Kernel_modesetting
   NOTE: the proprietary Nvidia driver does not provide a framebuffer so you will need to use Nouveau instead.
   
   
4. Install Plymouth
   I would have much preferred to use fbsplash (love the framebuffer console decorations) but it flickers too much so plymouth is really the only option. Install it as follows:
   https://wiki.gentoo.org/wiki/Plymouth
   and create an initramfs as detailed in the wiki (I used genkernel-next for this). Also make sure that udev_log=3 in /etc/udev/udev.conf or you may get an INIT message when the initrd loads.
   NOTE: you do not actually need a splash theme as such, you can just have a black splash screen.
   BUGS: if you're using openrc then you need to use sys-boot/plymouth-0.8.8 (which is no longer in tree) as per bug 621470. Also, you'll want to patch sys-boot/plymouth-openrc-plugin as per the last comment in bug 491194 so that plymouth displays correctly on shutdown.
   
   
5. Silence Openrc
   By default, openrc (or rather sys-apps/sysvinit) is really quite verbose on shutdown but can be silenced by patching the sysvinit sources to remove the various printouts/warnings from init.c and shutdown.c and by patching inittab to redirect the output of shutdown and reboot to /dev/null as per post 4802102. Again, I created a patched sys-apps/sysvinit in a local portage overlay (see next post for the patch).
   
   
6. Enable Logging
   Finally, to stop various stderr/stdout messages overwriting the splash screen, install a system logger such as app-admin/syslog-ng to redirect them to a log file/another console instead.
   

That's it, let me know if you have any comments/questions/suggestions.

[Jari_42]

Patch for silent sys-apps/sysvinit-2.88: