| /* 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" |
| |
| #define MAX_BUF 100 |
| |
| static wait_queue_head_t fb_state_wq; |
| static int display = 1; |
| 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"); |
| if (display == 1) { |
| display = 0; |
| sysfs_notify(power_kobj, NULL, "wait_for_fb_status"); |
| } |
| } |
| |
| 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"); |
| if (display == 0) { |
| display = 1; |
| sysfs_notify(power_kobj, NULL, "wait_for_fb_status"); |
| } |
| } |
| return s - buf; |
| } |
| |
| static ssize_t wait_for_fb_status_show(struct kobject *kobj, |
| struct kobj_attribute *attr, char *buf) |
| { |
| int ret = 0; |
| |
| if (display == 1) |
| ret = snprintf(buf, strnlen("on", MAX_BUF) + 1, "on"); |
| else |
| ret = snprintf(buf, strnlen("off", MAX_BUF) + 1, "off"); |
| |
| return ret; |
| } |
| |
| #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); |
| power_ro_attr(wait_for_fb_status); |
| |
| static struct attribute *g[] = { |
| &wait_for_fb_sleep_attr.attr, |
| &wait_for_fb_wake_attr.attr, |
| &wait_for_fb_status_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); |
| |