printk: add console_suspend module parameter
We are enabling some power features on medfield. To test suspend-2-RAM
conveniently, we need turn on/off console_suspend_enabled frequently.
Add a module parameter, so users could change it by:
/sys/module/printk/parameters/console_suspend
Signed-off-by: Yanmin Zhang <yanmin_zhang@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 106efe1..c2efe28 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1669,6 +1669,11 @@
debugging driver suspend/resume hooks). This may
not work reliably with all consoles, but is known
to work with serial and VGA consoles.
+ To facilitate more flexible debugging, we also add
+ console_suspend, a printk module parameter to control
+ it. Users could use console_suspend (usually
+ /sys/module/printk/parameters/console_suspend) to
+ turn on/off it dynamically.
noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
caches in the slab allocator. Saves per-node memory,
diff --git a/kernel/printk.c b/kernel/printk.c
index e62f949..6d9dedd 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -1111,6 +1111,10 @@
return 1;
}
__setup("no_console_suspend", console_suspend_disable);
+module_param_named(console_suspend, console_suspend_enabled,
+ bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(console_suspend, "suspend console during suspend"
+ " and hibernate operations");
/**
* suspend_console - suspend the console subsystem