Fixes and cleanups for earlyprintk aka boot console
commit69331af79cf29e26d1231152a172a1a10c2df511
authorGerd Hoffmann <kraxel@suse.de>
Tue, 8 May 2007 07:26:49 +0000 (8 00:26 -0700)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Tue, 8 May 2007 18:15:04 +0000 (8 11:15 -0700)
tree0c6f805fc78c1969b8c46f02070cb9dc39f3f944
parent6ae9200f2cab7b328e505fc9a7021db64e0590cf
Fixes and cleanups for earlyprintk aka boot console

The console subsystem already has an idea of a boot console, using the
CON_BOOT flag.  The implementation has some flaws though.  The major
problem is that presence of a boot console makes register_console() ignore
any other console devices (unless explicitly specified on the kernel
command line).

This patch fixes the console selection code to *not* consider a boot
console a full-featured one, so the first non-boot console registering will
become the default console instead.  This way the unregister call for the
boot console in the register_console() function actually triggers and the
handover from the boot console to the real console device works smoothly.
Added a printk for the handover, so you know which console device the
output goes to when the boot console stops printing messages.

The disable_early_printk() call is obsolete with that patch, explicitly
disabling the early console isn't needed any more as it works automagically
with that patch.

I've walked through the tree, dropped all disable_early_printk() instances
found below arch/ and tagged the consoles with CON_BOOT if needed.  The
code is tested on x86, sh (thanks to Paul) and mips (thanks to Ralf).

Changes to last version: Rediffed against -rc3, adapted to mips cleanups by
Ralf, fixed "udbg-immortal" cmd line arg on powerpc.

Signed-off-by: Gerd Hoffmann <kraxel@exsuse.de>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Andi Kleen <ak@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arch/alpha/kernel/setup.c
arch/alpha/kernel/srmcons.c
arch/mips/kernel/early_printk.c
arch/powerpc/kernel/udbg.c
arch/sh/kernel/early_printk.c
arch/sh64/kernel/early_printk.c
arch/x86_64/kernel/early_printk.c
drivers/char/tty_io.c
kernel/printk.c