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>

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>
Yanmin Zhang · Linus Torvalds
1 parent 0eca6b7c78
Showing 2 changed files with 9 additions and 0 deletions Side-by-side Diff
Documentation/kernel-parameters.txt
kernel/printk.c
@@ -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,
@@ -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
...	...	@@ -1669,6 +1669,11 @@
1669	1669	debugging driver suspend/resume hooks). This may
1670	1670	not work reliably with all consoles, but is known
1671	1671	to work with serial and VGA consoles.
	1672	+ To facilitate more flexible debugging, we also add
	1673	+ console_suspend, a printk module parameter to control
	1674	+ it. Users could use console_suspend (usually
	1675	+ /sys/module/printk/parameters/console_suspend) to
	1676	+ turn on/off it dynamically.
1672	1677
1673	1678	noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1674	1679	caches in the slab allocator. Saves per-node memory,
...	...	@@ -1111,6 +1111,10 @@
1111	1111	return 1;
1112	1112	}
1113	1113	__setup("no_console_suspend", console_suspend_disable);
	1114	+module_param_named(console_suspend, console_suspend_enabled,
	1115	+ bool, S_IRUGO \| S_IWUSR);
	1116	+MODULE_PARM_DESC(console_suspend, "suspend console during suspend"
	1117	+ " and hibernate operations");
1114	1118
1115	1119	/**
1116	1120	* suspend_console - suspend the console subsystem