From bfe8df3d314bddf30758bd738e0087e80964760c Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Tue, 16 Oct 2007 01:23:46 -0700 Subject: slow down printk during boot Optionally add a boot delay after each kernel printk() call, crudely measured in milliseconds, with a maximum delay of 10 seconds per printk. Enable CONFIG_BOOT_PRINTK_DELAY=y and then add (e.g.): "lpj=loops_per_jiffy boot_delay=100" to the kernel command line. It has been useful in cases like "during boot, my machine just reboots or the screen goes black" by slowing down printk, (and adding initcall_debug), we can usually see the last thing that happened before the lights went out which is usually a valuable clue. [akpm@linux-foundation.org: not all architectures implement CONFIG_HZ] [akpm@linux-foundation.org: fix lots of stuff] [bunk@stusta.de: kernel/printk.c: make 2 variables static] [heiko.carstens@de.ibm.com: fix slow down printk on boot compile error] Signed-off-by: Randy Dunlap Signed-off-by: Dave Jones Signed-off-by: Adrian Bunk Signed-off-by: Heiko Carstens Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- init/calibrate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'init') diff --git a/init/calibrate.c b/init/calibrate.c index 40ff3b40489..2d3d73bd4ce 100644 --- a/init/calibrate.c +++ b/init/calibrate.c @@ -10,7 +10,7 @@ #include -static unsigned long preset_lpj; +unsigned long preset_lpj; static int __init lpj_setup(char *str) { preset_lpj = simple_strtoul(str,NULL,0); -- cgit v1.2.3-70-g09d2