Merge in hotness from upstream.

Signed-off-by: Andres Salomon <dilinger@debian.org>

2 files changed, 22 insertions, 13 deletions

diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 8db07bd2d156..79833170bb9c 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -37,18 +37,6 @@ config PM_DEBUG
 	code. This is helpful when debugging and reporting PM bugs, like
 	suspend support.
 
-config DISABLE_SUSPEND_VT_SWITCH
-	bool "Disable the console switch prior to suspend (DANGEROUS)"
-	depends on VT_CONSOLE && PM && EXPERIMENTAL
-	---help---
-	This option disables the automatic switch to VT console that happens
-	prior to Linux going into a suspend/sleep.  Your video card/framebuffer
-	must be able to properly restore the display (even if X is doing
-	something crazy!) in this scenario.  This is useful for saving
-	precious milliseconds during suspend and resume.
-
-	If unsure, say N.
-
 config PM_VERBOSE
 	bool "Verbose Power Management debugging"
 	depends on PM_DEBUG
diff --git a/kernel/power/console.c b/kernel/power/console.c
index dca98f59b7cb..71ed4aa95fdc 100644
--- a/kernel/power/console.c
+++ b/kernel/power/console.c
@@ -7,15 +7,33 @@
 #include <linux/vt_kern.h>
 #include <linux/kbd_kern.h>
 #include <linux/console.h>
+#include <linux/module.h>
 #include "power.h"
 
-#if defined(CONFIG_VT) && defined(CONFIG_VT_CONSOLE) && !defined(CONFIG_DISABLE_SUSPEND_VT_SWITCH)
+#if defined(CONFIG_VT) && defined(CONFIG_VT_CONSOLE)
 #define SUSPEND_CONSOLE	(MAX_NR_CONSOLES-1)
 
 static int orig_fgconsole, orig_kmsg;
+static int disable_vt_switch;
+
+/*
+ * Normally during a suspend, we allocate a new console and switch to it.
+ * When we resume, we switch back to the original console.  This switch
+ * can be slow, so on systems where the framebuffer can handle restoration
+ * of video registers anyways, there's little point in doing the console
+ * switch.  This function allows you to disable it by passing it '0'.
+ */
+void pm_set_vt_switch(int do_switch)
+{
+	disable_vt_switch = !do_switch;
+}
+EXPORT_SYMBOL(pm_set_vt_switch);
 
 int pm_prepare_console(void)
 {
+	if (disable_vt_switch)
+		return 0;
+
 	acquire_console_sem();
 
 	orig_fgconsole = fg_console;
@@ -49,6 +67,9 @@ int pm_prepare_console(void)
 
 void pm_restore_console(void)
 {
+	if (disable_vt_switch)
+		return;
+
 	acquire_console_sem();
 	set_console(orig_fgconsole);
 	release_console_sem();