1 files changed, 83 insertions, 0 deletions
diff --git a/kernel/power/console.c b/kernel/power/console.c
new file mode 100644
index 0000000..b8628be
--- /dev/null
+++ b/kernel/power/console.c
@@ -0,0 +1,83 @@
+/*
+ * drivers/power/process.c - Functions for saving/restoring console.
+ *
+ * Originally from swsusp.
+ */
+
+#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)
+#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)
+{
+	acquire_console_sem();
+	disable_vt_switch = !do_switch;
+	release_console_sem();
+}
+EXPORT_SYMBOL(pm_set_vt_switch);
+
+int pm_prepare_console(void)
+{
+	acquire_console_sem();
+
+	if (disable_vt_switch) {
+		release_console_sem();
+		return 0;
+	}
+
+	orig_fgconsole = fg_console;
+
+	if (vc_allocate(SUSPEND_CONSOLE)) {
+	  /* we can't have a free VC for now. Too bad,
+	   * we don't want to mess the screen for now. */
+		release_console_sem();
+		return 1;
+	}
+
+	if (set_console(SUSPEND_CONSOLE)) {
+		/*
+		 * We're unable to switch to the SUSPEND_CONSOLE.
+		 * Let the calling function know so it can decide
+		 * what to do.
+		 */
+		release_console_sem();
+		return 1;
+	}
+	release_console_sem();
+
+	if (vt_waitactive(SUSPEND_CONSOLE)) {
+		pr_debug("Suspend: Can't switch VCs.");
+		return 1;
+	}
+	orig_kmsg = kmsg_redirect;
+	kmsg_redirect = SUSPEND_CONSOLE;
+	return 0;
+}
+
+void pm_restore_console(void)
+{
+	acquire_console_sem();
+	if (disable_vt_switch) {
+		release_console_sem();
+		return;
+	}
+	set_console(orig_fgconsole);
+	release_console_sem();
+	kmsg_redirect = orig_kmsg;
+}
+#endif