console: make blank timeout value a boot option

The console blank timer is currently hardcoded to 10*60 seconds which
might be annoying on systems with no input devices attached to wake up the
console again.  Especially during development, disabling the screen saver
can be handy - for example when debugging the root fs mount mechanism or
other scenarios where no userspace program could be started to do that at
runtime from userspace.

This patch defines a core_param for the variable in charge which allows
users to entirely disable the blank feature at boot time by setting it 0.
The value can still be overwritten at runtime using the standard ioctl
call - this just allows to conditionally change the default.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index ad3800630772..5578248c18a4 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -546,6 +546,10 @@ and is between 256 and 4096 characters. It is defined in the file
                         console=brl,ttyS0
                 For now, only VisioBraille is supported.
 
+        consoleblank=   [KNL] The console blank (screen saver) timeout in
+                        seconds. Defaults to 10*60 = 10mins. A value of 0
+                        disables the blank timer.
+
         coredump_filter=
                         [KNL] Change the default value for
                         /proc/<pid>/coredump_filter.