Re: echo mem > /sys/power/state

[Johannes Weiner <hannes@saeurebad.de>]

Hi,

Pavel Machek <pavel@ucw.cz> writes:

> diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
> index 29cf145..d830ed2 100644
> --- a/drivers/rtc/rtc-cmos.c
> +++ b/drivers/rtc/rtc-cmos.c
> @@ -78,7 +78,7 @@ static inline int is_intr(u8 rtc_intr)
>  
>  /*----------------------------------------------------------------*/
>  
> -static int cmos_read_time(struct device *dev, struct rtc_time *t)
> +int cmos_read_time(struct device *dev, struct rtc_time *t)
>  {
>  	/* REVISIT:  if the clock has a "century" register, use
>  	 * that instead of the heuristic in get_rtc_time().
> @@ -170,7 +170,7 @@ static int cmos_read_alarm(struct device
>  	return 0;
>  }
>  
> -static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
> +int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
>  {
>  	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
>  	unsigned char	mon, mday, hrs, min, sec;
> @@ -394,6 +394,7 @@ static const struct rtc_class_ops cmos_r
>  /*----------------------------------------------------------------*/
>  
>  static struct cmos_rtc	cmos_rtc;
> +struct device *pc_rtc_device;
>  
>  static irqreturn_t cmos_interrupt(int irq, void *p)
>  {
> @@ -431,6 +432,8 @@ cmos_do_probe(struct device *dev, struct
>  	if (cmos_rtc.dev)
>  		return -EBUSY;
>  
> +	pc_rtc_device = dev;
> +
>  	if (!ports)
>  		return -ENODEV;
>  
> @@ -546,7 +549,7 @@ cleanup0:
>  
>  static void cmos_do_shutdown(void)
>  {
> -	unsigned char	rtc_control;
> +	unsigned char rtc_control;
>  
>  	spin_lock_irq(&rtc_lock);
>  	rtc_control = CMOS_READ(RTC_CONTROL);
> diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
> index 8e186c6..b719fd3 100644
> --- a/kernel/power/Kconfig
> +++ b/kernel/power/Kconfig
> @@ -53,14 +53,20 @@ config PM_TRACE
>  	RTC across reboots, so that you can debug a machine that just hangs
>  	during suspend (or more commonly, during resume).
>  
> -	To use this debugging feature you should attempt to suspend the machine,
> -	then reboot it, then run
> +	To use this debugging feature you should attempt to suspend the
> +	machine, then reboot it, then run
>  
>  		dmesg -s 1000000 | grep 'hash matches'
>  
>  	CAUTION: this option will cause your machine's real-time clock to be
>  	set to an invalid time after a resume.
>  
> +config PM_SLEEPY_TEST
> +	bool "Test suspend/resume during bootup"
> +	depends on PM_DEBUG && PM_SLEEP && RTC_DRV_CMOS
> +	---help---
> +	This option will suspend/resume your machine during bootup.
> +
>  config PM_SLEEP_SMP
>  	bool
>  	depends on SUSPEND_SMP_POSSIBLE || HIBERNATION_SMP_POSSIBLE
> diff --git a/kernel/power/Makefile b/kernel/power/Makefile
> index f7dfff2..e5693d6 100644
> --- a/kernel/power/Makefile
> +++ b/kernel/power/Makefile
> @@ -5,7 +5,7 @@ endif
>  
>  obj-y				:= main.o
>  obj-$(CONFIG_PM_LEGACY)		+= pm.o
> -obj-$(CONFIG_PM_SLEEP)		+= process.o console.o
> +obj-$(CONFIG_PM_SLEEP)		+= process.o console.o sleepy.o

Why compiling it uncoditionally?  What would be wrong with

obj-$(CONFIG_PM_SLEEPY_TEST		+= sleepy.o

(besides the missing parenthesis, of course)?

>  obj-$(CONFIG_HIBERNATION)	+= swsusp.o disk.o snapshot.o swap.o user.o
>  
>  obj-$(CONFIG_MAGIC_SYSRQ)	+= poweroff.o
> diff --git a/kernel/power/sleepy.c b/kernel/power/sleepy.c
> new file mode 100644
> index 0000000..a437054
> --- /dev/null
> +++ b/kernel/power/sleepy.c
> @@ -0,0 +1,70 @@
> +/*
> + * Copyright (c) 2007 Pavel Machek <pavel@suse.cz>
> + * 
> + * This file is released under the GPLv2
> + *
> + */
> +
> +#include <linux/module.h>
> +#include <linux/suspend.h>
> +#include <linux/kobject.h>
> +#include <linux/string.h>
> +#include <linux/delay.h>
> +#include <linux/errno.h>
> +#include <linux/init.h>
> +#include <linux/console.h>
> +#include <linux/cpu.h>
> +#include <linux/resume-trace.h>
> +#include <linux/freezer.h>
> +#include <linux/vmstat.h>
> +#include <linux/syscalls.h>
> +#include <linux/rtc.h>
> +
> +#include <asm/percpu.h>
> +
> +#include "power.h"
> +
> +extern int set_alarm(int length);

Huh?

> +
> +extern struct device *pc_rtc_device;
> +extern int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t);
> +extern int cmos_read_time(struct device *dev, struct rtc_time *t);
> +
> +int set_alarm(int length)
> +{
> +	ssize_t retval;
> +	unsigned long now, alarm;
> +	struct rtc_wkalrm alm;
> +	struct rtc_device *rtc = to_rtc_device(pc_rtc_device);
> +
> +	retval = cmos_read_time(pc_rtc_device, &alm.time);
> +	if (retval < 0) {
> +		printk("Auto sleep: can't get time?\n");
> +		return retval;
> +	}
> +	rtc_tm_to_time(&alm.time, &now);
> +	printk("Auto sleep: Now %ld\n", now);
> +
> +	alarm = now+length;
> +	rtc_time_to_tm(alarm, &alm.time);
> +
> +	retval = cmos_set_alarm(rtc, &alm);

cmos_set_alarm() takes a struct device * too.

> +	if (retval < 0) {
> +		printk("Auto sleep: can't set alarm.\n");
> +		return retval;
> +	}
> +	printk("Auto sleep: Alarm set\n");
> +	return 0;
> +}
> +
> +#ifdef CONFIG_PM_SLEEPY_TEST
> +static int
> +test_sleep(void)
> +{
> +	set_alarm(5);
> +	pm_suspend(PM_SUSPEND_MEM);
> +	return 0;
> +}
> +
> +late_initcall(test_sleep);
> +#endif

	Hannes