• Fabio M. Di Nitto's avatar
    console: allow to retain boot console via boot option keep_bootcon · 7bf69395
    Fabio M. Di Nitto authored
    On some architectures, the boot process involves de-registering the boot
    console (early boot), initialize drivers and then re-register the console.
    
    This mechanism introduces a window in which no printk can happen on the
    console and messages are buffered and then printed once the new console is
    available.
    
    If a kernel crashes during this window, all it's left on the boot console
    is "console [foo] enabled, bootconsole disabled" making debug of the crash
    rather 'interesting'.
    
    By adding "keep_bootcon" option, do not unregister the boot console, that
    will allow to printk everything that is happening up to the crash.
    
    The option is clearly meant only for debugging purposes as it introduces
    lots of duplicated info printed on console, but will make bug report from
    users easier as it doesn't require a kernel build just to figure out where
    we crash.
    Signed-off-by: default avatarFabio M. Di Nitto <fabbione@fabbione.net>
    Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
    Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
    Cc: Greg KH <gregkh@suse.de>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    7bf69395
kernel-parameters.txt 92.1 KB