• Gerd Hoffmann's avatar
    Fixes and cleanups for earlyprintk aka boot console · 69331af7
    Gerd Hoffmann authored
    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    The disable_early_printk() call is obsolete with that patch, explicitly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: default avatarGerd Hoffmann <kraxel@exsuse.de>
    Acked-by: default avatarPaul Mundt <lethal@linux-sh.org>
    Acked-by: default avatarRalf 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: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    69331af7
early_printk.c 4.47 KB