PM: earlysuspend: Add console switch when user requested sleep state changes.

Signed-off-by: Arve Hjønnevåg <arve@android.com>

3 files changed, 96 insertions, 0 deletions

diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 7bd02a13d3d3..a6560e69621b 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -172,6 +172,23 @@ config EARLYSUSPEND
 	  Call early suspend handlers when the user requested sleep state
 	  changes.
 
+choice
+	prompt "User-space screen access"
+	default CONSOLE_EARLYSUSPEND
+	depends on HAS_EARLYSUSPEND
+
+	config NO_USER_SPACE_SCREEN_ACCESS_CONTROL
+		bool "None"
+
+	config CONSOLE_EARLYSUSPEND
+		bool "Console switch on early-suspend"
+		depends on HAS_EARLYSUSPEND && VT
+		---help---
+		  Register early suspend handler to perform a console switch to
+		  when user-space should stop drawing to the screen and a switch
+		  back when it should resume.
+endchoice
+
 config HIBERNATION
 	bool "Hibernation (aka 'suspend to disk')"
 	depends on PM && SWAP && ARCH_HIBERNATION_POSSIBLE
diff --git a/kernel/power/Makefile b/kernel/power/Makefile
index 2a1fce2d2780..fbe814bc0b53 100644
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -10,5 +10,6 @@ obj-$(CONFIG_HIBERNATION)	+= hibernate.o snapshot.o swap.o user.o \
 obj-$(CONFIG_WAKELOCK)		+= wakelock.o
 obj-$(CONFIG_USER_WAKELOCK)	+= userwakelock.o
 obj-$(CONFIG_EARLYSUSPEND)	+= earlysuspend.o
+obj-$(CONFIG_CONSOLE_EARLYSUSPEND)	+= consoleearlysuspend.o
 
 obj-$(CONFIG_MAGIC_SYSRQ)	+= poweroff.o
diff --git a/kernel/power/consoleearlysuspend.c b/kernel/power/consoleearlysuspend.c
new file mode 100644
index 000000000000..a8befb419158
--- /dev/null
+++ b/kernel/power/consoleearlysuspend.c
@@ -0,0 +1,78 @@
+/* kernel/power/consoleearlysuspend.c
+ *
+ * Copyright (C) 2005-2008 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/console.h>
+#include <linux/earlysuspend.h>
+#include <linux/kbd_kern.h>
+#include <linux/module.h>
+#include <linux/vt_kern.h>
+#include <linux/wait.h>
+
+#define EARLY_SUSPEND_CONSOLE	(MAX_NR_CONSOLES-1)
+
+static int orig_fgconsole;
+static void console_early_suspend(struct early_suspend *h)
+{
+	acquire_console_sem();
+	orig_fgconsole = fg_console;
+	if (vc_allocate(EARLY_SUSPEND_CONSOLE))
+		goto err;
+	if (set_console(EARLY_SUSPEND_CONSOLE))
+		goto err;
+	release_console_sem();
+
+	if (vt_waitactive(EARLY_SUSPEND_CONSOLE))
+		pr_warning("console_early_suspend: Can't switch VCs.\n");
+	return;
+err:
+	pr_warning("console_early_suspend: Can't set console\n");
+	release_console_sem();
+}
+
+static void console_late_resume(struct early_suspend *h)
+{
+	int ret;
+	acquire_console_sem();
+	ret = set_console(orig_fgconsole);
+	release_console_sem();
+	if (ret) {
+		pr_warning("console_late_resume: Can't set console.\n");
+		return;
+	}
+
+	if (vt_waitactive(orig_fgconsole))
+		pr_warning("console_late_resume: Can't switch VCs.\n");
+}
+
+static struct early_suspend console_early_suspend_desc = {
+	.level = EARLY_SUSPEND_LEVEL_STOP_DRAWING,
+	.suspend = console_early_suspend,
+	.resume = console_late_resume,
+};
+
+static int __init console_early_suspend_init(void)
+{
+	register_early_suspend(&console_early_suspend_desc);
+	return 0;
+}
+
+static void  __exit console_early_suspend_exit(void)
+{
+	unregister_early_suspend(&console_early_suspend_desc);
+}
+
+module_init(console_early_suspend_init);
+module_exit(console_early_suspend_exit);
+