[PATCH 11/13] PM: earlysuspend: Removing dependence on console.

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From: Rebecca Schultz <rschultz@xxxxxxxxxx>
Rather than signaling a full update of the display from userspace via aconsole switch, this patch introduces 2 files int /sys/power,wait_for_fb_sleep and wait_for_fb_wake.  Reading these files will blockuntil the requested state has been entered.  When a read fromwait_for_fb_sleep returns userspace should stop drawing.  Whenwait_for_fb_wake returns, it should do a full update.  If either are calledwhen the fb driver is already in the requested state, they will returnimmediately.
Signed-off-by: Rebecca Schultz <rschultz@xxxxxxxxxx>Signed-off-by: Arve Hjønnevåg <arve@xxxxxxxxxxx>--- kernel/power/Kconfig          |    9 +++ kernel/power/Makefile         |    1 + kernel/power/fbearlysuspend.c |  153 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 163 insertions(+), 0 deletions(-) create mode 100644 kernel/power/fbearlysuspend.c
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfigindex f1a3d5c..616341d 100644--- a/kernel/power/Kconfig+++ b/kernel/power/Kconfig@@ -168,6 +168,7 @@ config EARLYSUSPEND  choice 	prompt "User-space screen access"+	default FB_EARLYSUSPEND if !FRAMEBUFFER_CONSOLE 	default CONSOLE_EARLYSUSPEND 	depends on HAS_EARLYSUSPEND @@ -181,6 +182,14 @@ choice 		  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.++	config FB_EARLYSUSPEND+		bool "Sysfs interface"+		depends on HAS_EARLYSUSPEND+		---help---+		  Register early suspend handler that notifies and waits for+		  user-space through sysfs when user-space should stop drawing+		  to the screen and notifies user-space when it should resume. endchoice  config HIBERNATIONdiff --git a/kernel/power/Makefile b/kernel/power/Makefileindex 8bf293d..5beaa21 100644--- a/kernel/power/Makefile+++ b/kernel/power/Makefile@@ -10,6 +10,7 @@ obj-$(CONFIG_WAKELOCK)		+= wakelock.o obj-$(CONFIG_USER_WAKELOCK)	+= userwakelock.o obj-$(CONFIG_EARLYSUSPEND)	+= earlysuspend.o obj-$(CONFIG_CONSOLE_EARLYSUSPEND)	+= consoleearlysuspend.o+obj-$(CONFIG_FB_EARLYSUSPEND)	+= fbearlysuspend.o obj-$(CONFIG_HIBERNATION)	+= swsusp.o disk.o snapshot.o swap.o user.o  obj-$(CONFIG_MAGIC_SYSRQ)	+= poweroff.odiff --git a/kernel/power/fbearlysuspend.c b/kernel/power/fbearlysuspend.cnew file mode 100644index 0000000..1513765--- /dev/null+++ b/kernel/power/fbearlysuspend.c@@ -0,0 +1,153 @@+/* kernel/power/fbearlysuspend.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/earlysuspend.h>+#include <linux/module.h>+#include <linux/wait.h>++#include "power.h"++static wait_queue_head_t fb_state_wq;+static DEFINE_SPINLOCK(fb_state_lock);+static enum {+	FB_STATE_STOPPED_DRAWING,+	FB_STATE_REQUEST_STOP_DRAWING,+	FB_STATE_DRAWING_OK,+} fb_state;++/* tell userspace to stop drawing, wait for it to stop */+static void stop_drawing_early_suspend(struct early_suspend *h)+{+	int ret;+	unsigned long irq_flags;++	spin_lock_irqsave(&fb_state_lock, irq_flags);+	fb_state = FB_STATE_REQUEST_STOP_DRAWING;+	spin_unlock_irqrestore(&fb_state_lock, irq_flags);++	wake_up_all(&fb_state_wq);+	ret = wait_event_timeout(fb_state_wq,+				 fb_state == FB_STATE_STOPPED_DRAWING,+				 HZ);+	if (unlikely(fb_state != FB_STATE_STOPPED_DRAWING))+		pr_warning("stop_drawing_early_suspend: timeout waiting for "+			   "userspace to stop drawing\n");+}++/* tell userspace to start drawing */+static void start_drawing_late_resume(struct early_suspend *h)+{+	unsigned long irq_flags;++	spin_lock_irqsave(&fb_state_lock, irq_flags);+	fb_state = FB_STATE_DRAWING_OK;+	spin_unlock_irqrestore(&fb_state_lock, irq_flags);+	wake_up(&fb_state_wq);+}++static struct early_suspend stop_drawing_early_suspend_desc = {+	.level = EARLY_SUSPEND_LEVEL_STOP_DRAWING,+	.suspend = stop_drawing_early_suspend,+	.resume = start_drawing_late_resume,+};++static ssize_t wait_for_fb_sleep_show(struct kobject *kobj,+				      struct kobj_attribute *attr, char *buf)+{+	char *s = buf;+	int ret;++	ret = wait_event_interruptible(fb_state_wq,+				       fb_state != FB_STATE_DRAWING_OK);+	if (ret && fb_state == FB_STATE_DRAWING_OK)+		return ret;+	else+		s += sprintf(buf, "sleeping");+	return s - buf;+}++static ssize_t wait_for_fb_wake_show(struct kobject *kobj,+				     struct kobj_attribute *attr, char *buf)+{+	char *s = buf;+	int ret;+	unsigned long irq_flags;++	spin_lock_irqsave(&fb_state_lock, irq_flags);+	if (fb_state == FB_STATE_REQUEST_STOP_DRAWING) {+		fb_state = FB_STATE_STOPPED_DRAWING;+		wake_up(&fb_state_wq);+	}+	spin_unlock_irqrestore(&fb_state_lock, irq_flags);++	ret = wait_event_interruptible(fb_state_wq,+				       fb_state == FB_STATE_DRAWING_OK);+	if (ret && fb_state != FB_STATE_DRAWING_OK)+		return ret;+	else+		s += sprintf(buf, "awake");++	return s - buf;+}++#define power_ro_attr(_name) \+static struct kobj_attribute _name##_attr = {	\+	.attr	= {				\+		.name = __stringify(_name),	\+		.mode = 0444,			\+	},					\+	.show	= _name##_show,			\+	.store	= NULL,		\+}++power_ro_attr(wait_for_fb_sleep);+power_ro_attr(wait_for_fb_wake);++static struct attribute *g[] = {+	&wait_for_fb_sleep_attr.attr,+	&wait_for_fb_wake_attr.attr,+	NULL,+};++static struct attribute_group attr_group = {+	.attrs = g,+};++static int __init android_power_init(void)+{+	int ret;++	init_waitqueue_head(&fb_state_wq);+	fb_state = FB_STATE_DRAWING_OK;++	ret = sysfs_create_group(power_kobj, &attr_group);+	if (ret) {+		pr_err("android_power_init: sysfs_create_group failed\n");+		return ret;+	}++	register_early_suspend(&stop_drawing_early_suspend_desc);+	return 0;+}++static void  __exit android_power_exit(void)+{+	unregister_early_suspend(&stop_drawing_early_suspend_desc);+	sysfs_remove_group(power_kobj, &attr_group);+}++module_init(android_power_init);+module_exit(android_power_exit);+-- 1.6.1
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