tty: add 'active' sysfs attribute to tty0 and console device

tty: add 'active' sysfs attribute to tty0 and console device

Userspace can query the actual virtual console, and the configured
console devices behind /dev/tt0 and /dev/console.

The last entry in the list of devices is the active device, analog
to the console= kernel command line option.

The attribute supports poll(), which is raised when the virtual
console is changed or /dev/console is reconfigured.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

index 0000000..b138b66

1 files changed, 1 insertions, 1 deletions

diff --git a/include/linux/console.h b/include/linux/console.h
index 875cfb1c8132..9774fe6a1a97 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -151,7 +151,7 @@ extern int is_console_locked(void);
 extern int braille_register_console(struct console *, int index,
                 char *console_options, char *braille_options);
 extern int braille_unregister_console(struct console *);
-
+extern void console_sysfs_notify(void);
 extern int console_suspend_enabled;
 
 /* Suspend and resume console messages over PM events */