From: Steven Rostedt (VMware) rostedt@goodmis.org
There's been discussion on the fb list about the addition of WARN_CONSOLE_UNLOCKED() inside the fb code. The complaint is that when the fb module is loaded with lockless_register_fb the console lock is not taken for debugging reasons. With the addition of WARN_CONSOLE_UNLOCK() within the fb code, this causes the console to fill up with warnings when trying to debug the fb driver.
There's also a #if 1 that enables the warning which was added before git history, and we look down on constant #if's in the kernel nowadays anyway.
Remove the #if 1 and add a ignore_console_lock_warning boolean that can be set by drivers to ignore the warning in order to do debugging.
Link: http://lkml.kernel.org/r/717e6337-e7a6-7a92-1c1b-8929a25696b5@suse.de Reviewed-by: Hans de Goede hdegoede@redhat.com Acked-by: Sergey Senozhatsky sergey.senozhatsky@gmail.com Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org --- Changes since V1: - Added comment to describe ignore_console_unlock_waring variable - Abide by 80 character limit
Index: linux-trace.git/include/linux/console.h =================================================================== --- linux-trace.git.orig/include/linux/console.h +++ linux-trace.git/include/linux/console.h @@ -200,11 +200,14 @@ void vcs_make_sysfs(int index); void vcs_remove_sysfs(int index);
/* Some debug stub to catch some of the obvious races in the VT code */ -#if 1 -#define WARN_CONSOLE_UNLOCKED() WARN_ON(!is_console_locked() && !oops_in_progress) -#else -#define WARN_CONSOLE_UNLOCKED() -#endif +#define WARN_CONSOLE_UNLOCKED() \ + WARN_ON(!ignore_console_lock_warning && \ + !is_console_locked() && !oops_in_progress) +/* + * Set ignore_console_lock_warning to true if you need to quiet + * WARN_CONSOLE_UNLOCKED() for debugging purposes. + */ +extern bool ignore_console_lock_warning;
/* VESA Blanking Levels */ #define VESA_NO_BLANKING 0 Index: linux-trace.git/kernel/printk/printk.c =================================================================== --- linux-trace.git.orig/kernel/printk/printk.c +++ linux-trace.git/kernel/printk/printk.c @@ -66,6 +66,9 @@ int console_printk[4] = { CONSOLE_LOGLEVEL_DEFAULT, /* default_console_loglevel */ };
+bool ignore_console_lock_warning __read_mostly; +EXPORT_SYMBOL(ignore_console_lock_warning); + /* * Low level drivers may need that to know if they can schedule in * their unblank() callback or not. So let's export it.