lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Fixes and cleanups for earlyprintk aka boot console

Browse Source 
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The disable_early_printk() call is obsolete with that patch, explicitly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>
This commit is contained in:
Gerd Hoffmann
2007-05-08 00:26:49 -07:00
committed by Linus Torvalds
parent 6ae9200f2c
commit 69331af79c
9 changed files with 35 additions and 77 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
arch/powerpc/kernel/udbg.c
View File

@@ -142,29 +142,22 @@ static void udbg_console_write(struct console *con, const char *s,
static struct console udbg_console = {
.name = "udbg",
.write = udbg_console_write,
.flags = CON_PRINTBUFFER | CON_ENABLED,
.flags = CON_PRINTBUFFER | CON_ENABLED | CON_BOOT,
.index = -1,
};
static int early_console_initialized;
void __init disable_early_printk(void)
{
if (!early_console_initialized)
return;
if (strstr(boot_command_line, "udbg-immortal")) {
printk(KERN_INFO "early console immortal !\n");
return;
}
unregister_console(&udbg_console);
early_console_initialized = 0;
}
/* called by setup_system */
void register_early_udbg_console(void)
{
if (early_console_initialized)
return;
if (strstr(boot_command_line, "udbg-immortal")) {
printk(KERN_INFO "early console immortal !\n");
udbg_console.flags &= ~CON_BOOT;
}
early_console_initialized = 1;
register_console(&udbg_console);
}