[PATCH 06/10] PM: Add early suspend api.

Arve Hjønnevåg
2009-02-11T01:49:11Z

If early-suspend support is enabled, early suspend handlers will be called
when a state other than "on" is written to /sys/power/request_state before
the unlocking "main" wakelock. Writing "on", locks the "main" wakelock and
calls the early-suspend resume handlers.

Signed-off-by: Arve Hjønnevåg <arve@android.com>
---
Documentation/power/early-suspend.txt | 26 +++++
include/linux/earlysuspend.h | 55 ++++++++++
kernel/power/Kconfig | 8 ++
kernel/power/Makefile | 1 +
kernel/power/earlysuspend.c | 174 +++++++++++++++++++++++++++++++++
kernel/power/power.h | 5 +
kernel/power/wakelock.c | 5 +
7 files changed, 274 insertions(+), 0 deletions(-)
create mode 100644 Documentation/power/early-suspend.txt
create mode 100755 include/linux/earlysuspend.h
create mode 100644 kernel/power/earlysuspend.c

diff --git a/Documentation/power/early-suspend.txt b/Documentation/power/early-suspend.txt
new file mode 100644
index 0000000..8286d3a
--- /dev/null
+++ b/Documentation/power/early-suspend.txt
@@ -0,0 +1,26 @@
+Early-suspend
+=============
+
+The early-suspend api allows drivers to get notified when user-space writes to
+/sys/power/request_state to indicate that the user visible sleep state should
+change. A level controls what order the handlers are called in. Suspend
+handlers are called in low to high level order, resume handlers are called in
+the opposite order.
+
+Four levels are defined:
+EARLY_SUSPEND_LEVEL_BLANK_SCREEN:
+ On suspend the screen should be turned off but the framebuffer must still be
+ accessible. On resume the screen can be turned back on.
+
+EARLY_SUSPEND_LEVEL_STOP_DRAWING:
+ On suspend this level notifies user-space that it should stop accessing the
+ framebuffer and it waits for it to complete. On resume it notifies user-space
+ that it should resume screen access.
+ Two methods are provided, console switch or a sysfs interface.
+
+EARLY_SUSPEND_LEVEL_DISABLE_FB:
+ Turn off the framebuffer on suspend and back on on resume.
+
+EARLY_SUSPEND_LEVEL_STOP_INPUT:
+ On suspend turn off input devices that are not capable of wakeup or where
+ wakeup is disabled. On resume turn the same devices back on.
diff --git a/include/linux/earlysuspend.h b/include/linux/earlysuspend.h
new file mode 100755
index 0000000..e3d03fb
--- /dev/null
+++ b/include/linux/earlysuspend.h
@@ -0,0 +1,55 @@
+/* include/linux/earlysuspend.h
+ *
+ * Copyright (C) 2007-2008 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.
+ *
+ */
+
+#ifndef _LINUX_EARLYSUSPEND_H
+#define _LINUX_EARLYSUSPEND_H
+
+#include <linux/list.h>
+
+/* The early_suspend structure defines suspend and resume hooks to be called
+ * when the user visible sleep state of the system changes, and a level to
+ * control the order. They can be used to turn off the screen and input
+ * devices that are not used for wakeup.
+ * Suspend handlers are called in low to high level order, resume handlers are
+ * called in the opposite order. If, when calling register_early_suspend,
+ * the suspend handlers have already been called without a matching call to the
+ * resume handlers, the suspend handler will be called directly from
+ * register_early_suspend. This direct call can violate the normal level order.
+ */
+enum {
+ EARLY_SUSPEND_LEVEL_BLANK_SCREEN = 50,
+ EARLY_SUSPEND_LEVEL_STOP_INPUT = 75,
+ EARLY_SUSPEND_LEVEL_STOP_DRAWING = 100,
+ EARLY_SUSPEND_LEVEL_DISABLE_FB = 150,
+};
+struct early_suspend {
+#ifdef CONFIG_EARLYSUSPEND
+ struct list_head link;
+ int level;
+ void (*suspend)(struct early_suspend *h);
+ void (*resume)(struct early_suspend *h);
+#endif
+};
+
+#ifdef CONFIG_EARLYSUSPEND
+void register_early_suspend(struct early_suspend *handler);
+void unregister_early_suspend(struct early_suspend *handler);
+#else
+#define register_early_suspend(handler) do { } while (0)
+#define unregister_early_suspend(handler) do { } while (0)
+#endif
+
+#endif
+
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index e784014..ccc55be 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -151,6 +151,14 @@ config USER_WAKELOCK
to create, lock and unlock a wakelock. The wakelock will be
deleted when the device is closed.

+config EARLYSUSPEND
+ bool "Early suspend"
+ depends on WAKELOCK
+ default y
+ ---help---
+ Call early suspend handlers when the user requested sleep state
+ changes.
+
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 63d30db..d3467b3 100644
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_PM_SLEEP) += console.o
obj-$(CONFIG_FREEZER) += process.o
obj-$(CONFIG_WAKELOCK) += wakelock.o
obj-$(CONFIG_USER_WAKELOCK) += userwakelock.o
+obj-$(CONFIG_EARLYSUSPEND) += earlysuspend.o
obj-$(CONFIG_HIBERNATION) += swsusp.o disk.o snapshot.o swap.o user.o

obj-$(CONFIG_MAGIC_SYSRQ) += poweroff.o
diff --git a/kernel/power/earlysuspend.c b/kernel/power/earlysuspend.c
new file mode 100644
index 0000000..4cdca39
--- /dev/null
+++ b/kernel/power/earlysuspend.c
@@ -0,0 +1,174 @@
+/* kernel/power/earlysuspend.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/mutex.h>
+#include <linux/rtc.h>
+#include <linux/syscalls.h> /* sys_sync */
+#include <linux/wakelock.h>
+#include <linux/workqueue.h>
+
+#include "power.h"
+
+enum {
+ DEBUG_SUSPEND = 1U << 0,
+ DEBUG_HANDLERS = 1U << 1,
+};
+static int debug_mask;
+module_param_named(debug_mask, debug_mask, int, S_IRUGO | S_IWUSR | S_IWGRP);
+
+static DEFINE_MUTEX(early_suspend_lock);
+static LIST_HEAD(early_suspend_handlers);
+static void early_suspend(struct work_struct *work);
+static void late_resume(struct work_struct *work);
+static DECLARE_WORK(early_suspend_work, early_suspend);
+static DECLARE_WORK(late_resume_work, late_resume);
+static DEFINE_SPINLOCK(state_lock);
+enum {
+ SUSPEND_REQUESTED = 0x1,
+ SUSPENDED = 0x2,
+ SUSPEND_REQUESTED_AND_SUSPENDED = SUSPEND_REQUESTED | SUSPENDED,
+};
+static int state;
+
+void register_early_suspend(struct early_suspend *handler)
+{
+ struct list_head *pos;
+
+ mutex_lock(&early_suspend_lock);
+ list_for_each(pos, &early_suspend_handlers) {
+ struct early_suspend *e;
+ e = list_entry(pos, struct early_suspend, link);
+ if (e->level > handler->level)
+ break;
+ }
+ list_add_tail(&handler->link, pos);
+ if ((state & SUSPENDED) && handler->suspend)
+ handler->suspend(handler);
+ mutex_unlock(&early_suspend_lock);
+}
+EXPORT_SYMBOL(register_early_suspend);
+
+void unregister_early_suspend(struct early_suspend *handler)
+{
+ mutex_lock(&early_suspend_lock);
+ list_del(&handler->link);
+ mutex_unlock(&early_suspend_lock);
+}
+EXPORT_SYMBOL(unregister_early_suspend);
+
+static void early_suspend(struct work_struct *work)
+{
+ struct early_suspend *pos;
+ unsigned long irqflags;
+ int abort = 0;
+
+ mutex_lock(&early_suspend_lock);
+ spin_lock_irqsave(&state_lock, irqflags);
+ if (state == SUSPEND_REQUESTED)
+ state |= SUSPENDED;
+ else
+ abort = 1;
+ spin_unlock_irqrestore(&state_lock, irqflags);
+
+ if (abort) {
+ if (debug_mask & DEBUG_SUSPEND)
+ pr_info("early_suspend: abort, state %d\n", state);
+ mutex_unlock(&early_suspend_lock);
+ goto abort;
+ }
+
+ if (debug_mask & DEBUG_SUSPEND)
+ pr_info("early_suspend: call handlers\n");
+ list_for_each_entry(pos, &early_suspend_handlers, link) {
+ if (pos->suspend) {
+ if (debug_mask & DEBUG_HANDLERS)
+ pr_info("early_suspend: call %pF\n",
+ pos->suspend);
+ pos->suspend(pos);
+ if (debug_mask & DEBUG_HANDLERS)
+ pr_info("early_suspend: %pF returned\n",
+ pos->suspend);
+ }
+ }
+ mutex_unlock(&early_suspend_lock);
+
+ if (debug_mask & DEBUG_SUSPEND)
+ pr_info("early_suspend: sync\n");
+
+ sys_sync();
+abort:
+ spin_lock_irqsave(&state_lock, irqflags);
+ if (state == SUSPEND_REQUESTED_AND_SUSPENDED)
+ wake_unlock(&main_wake_lock);
+ spin_unlock_irqrestore(&state_lock, irqflags);
+}
+
+static void late_resume(struct work_struct *work)
+{
+ struct early_suspend *pos;
+ unsigned long irqflags;
+ int abort = 0;
+
+ mutex_lock(&early_suspend_lock);
+ spin_lock_irqsave(&state_lock, irqflags);
+ if (state == SUSPENDED)
+ state = 0; /* clear SUSPENDED */
+ else
+ abort = 1;
+ spin_unlock_irqrestore(&state_lock, irqflags);
+
+ if (abort) {
+ if (debug_mask & DEBUG_SUSPEND)
+ pr_info("late_resume: abort, state %d\n", state);
+ goto abort;
+ }
+ if (debug_mask & DEBUG_SUSPEND)
+ pr_info("late_resume: call handlers\n");
+ list_for_each_entry_reverse(pos, &early_suspend_handlers, link)
+ if (pos->resume) {
+ if (debug_mask & DEBUG_HANDLERS)
+ pr_info("early_suspend: call %pF\n",
+ pos->resume);
+ pos->resume(pos);
+ if (debug_mask & DEBUG_HANDLERS)
+ pr_info("early_suspend: %pF returned\n",
+ pos->resume);
+ }
+ if (debug_mask & DEBUG_SUSPEND)
+ pr_info("late_resume: done\n");
+abort:
+ mutex_unlock(&early_suspend_lock);
+}
+
+void request_early_suspend_state(bool on)
+{
+ unsigned long irqflags;
+ int old_sleep;
+
+ spin_lock_irqsave(&state_lock, irqflags);
+ old_sleep = state & SUSPEND_REQUESTED;
+ if (!old_sleep && !on) {
+ state |= SUSPEND_REQUESTED;
+ queue_work(suspend_work_queue, &early_suspend_work);
+ } else if (old_sleep && on) {
+ state &= ~SUSPEND_REQUESTED;
+ wake_lock(&main_wake_lock);
+ queue_work(suspend_work_queue, &late_resume_work);
+ }
+ spin_unlock_irqrestore(&state_lock, irqflags);
+}
+
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 9468679..7d8538d 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -230,3 +230,8 @@ extern struct workqueue_struct *suspend_work_queue;
extern struct wake_lock main_wake_lock;
void request_suspend_state(suspend_state_t state);
#endif
+
+#ifdef CONFIG_EARLYSUSPEND
+/* kernel/power/earlysuspend.c */
+void request_early_suspend_state(bool on);
+#endif
diff --git a/kernel/power/wakelock.c b/kernel/power/wakelock.c
index c396b58..5048ad3 100644
--- a/kernel/power/wakelock.c
+++ b/kernel/power/wakelock.c
@@ -593,10 +593,15 @@ void request_suspend_state(suspend_state_t state)
tm.tm_hour, tm.tm_min, tm.tm_sec, ts.tv_nsec);
}
requested_suspend_state = state;
+
+#ifdef CONFIG_EARLYSUSPEND
+ request_early_suspend_state(state == PM_SUSPEND_ON);
+#else
if (state == PM_SUSPEND_ON)
wake_lock(&main_wake_lock);
else
wake_unlock(&main_wake_lock);
+#endif
spin_unlock_irqrestore(&state_lock, irqflags);
}

--
1.6.1

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