On Sunday, 3 of February 2008, David Brownell wrote:
> On Saturday 02 February 2008, Ingo Molnar wrote:
> > randconfig testing found the following build failure:
> >
> > kernel/built-in.o: In function `be_sleepy':
> > sleepy.c:(.init.text+0x1952): undefined reference to `rtc_class'
> > sleepy.c:(.init.text+0x1963): undefined reference to `rtc_class_open'
>
> Because:
>
> > CONFIG_RTC_LIB=m
>
> I think that the wakealarm test:
>
> > +config PM_WAKEALARM_TEST
> > + bool "Test suspend/resume and wakealarm during bootup"
> > + depends on SUSPEND && PM_DEBUG && RTC_LIB
I guess it also should depend on CONFIG_RTC_DRV_CMOS (not being a module)
and !CONFIG_RTC.
> should depend on RTC_LIB=y ... which will prevent that build error,
> but would still allow the RTC to live in a module.
>
> Updated patch appended ... it should address most config issues.
>
> - Dave
>
>
> ====== CUT HERE
> Updated verion of Pavel's "sleepy" test. This version doesn't depend on
> x86-specific RTC support, or suspend-to-RAM capability, and describes
> itself a bit better.
>
> Partially tested on an ARM board ... for some reason system sleep states
> are currently broken on that system (new behavior since 2.6.24), so this
> won't yet complete.
>
> Note a generic glitch: the message strings aren't in the same section
> as the function using them, so this has a bigger runtime footprint than
> it should ...
>
> ---
> drivers/char/Kconfig | 5 +-
> drivers/rtc/Kconfig | 1
> kernel/power/Kconfig | 17 ++++++-
> kernel/power/Makefile | 2
> kernel/power/sleepy.c | 113 ++++++++++++++++++++++++++++++++++++++++++++++++++
> 5 files changed, 134 insertions(+), 4 deletions(-)
>
> --- g26.orig/drivers/char/Kconfig 2008-02-02 22:42:15.000000000 -0800
> +++ g26/drivers/char/Kconfig 2008-02-02 22:51:53.000000000 -0800
> @@ -715,9 +715,12 @@ config NVRAM
> To compile this driver as a module, choose M here: the
> module will be called nvram.
>
> +comment "You are using the RTC framework, not the legacy CMOS RTC driver"
> + depends on RTC_DRV_CMOS
> +
> config RTC
> tristate "Enhanced Real Time Clock Support"
> - depends on !PPC && !PARISC && !IA64 && !M68K && !SPARC && !FRV && !ARM && !SUPERH && !S390
> + depends on !PPC && !PARISC && !IA64 && !M68K && !SPARC && !FRV && !ARM && !SUPERH && !S390 && !RTC_DRV_CMOS
> ---help---
> If you say Y here and create a character special file /dev/rtc with
> major number 10 and minor number 135 using mknod ("man mknod"), you
> --- g26.orig/drivers/rtc/Kconfig 2008-02-02 22:37:28.000000000 -0800
> +++ g26/drivers/rtc/Kconfig 2008-02-02 22:38:23.000000000 -0800
> @@ -281,6 +281,7 @@ comment "Platform RTC drivers"
> config RTC_DRV_CMOS
> tristate "PC-style 'CMOS'"
> depends on X86 || ALPHA || ARM || M32R || ATARI || PPC || MIPS
> + default y if X86
> help
> Say "yes" here to get direct support for the real time clock
> found in every PC or ACPI-based system, and some other boards.
> --- g26.orig/kernel/power/Kconfig 2008-02-02 22:30:21.000000000 -0800
> +++ g26/kernel/power/Kconfig 2008-02-02 23:28:56.000000000 -0800
> @@ -1,3 +1,6 @@
> +#
> +# Note that power management involves more than just system sleep states...
> +#
> config PM
> bool "Power Management support"
> depends on !IA64_HP_SIM
> @@ -74,8 +77,8 @@ config PM_TRACE_RTC
> 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'
>
> @@ -104,6 +107,16 @@ config SUSPEND
> powered and thus its contents are preserved, such as the
> suspend-to-RAM state (e.g. the ACPI S3 state).
>
> +config PM_WAKEALARM_TEST
> + bool "Test suspend/resume and wakealarm during bootup"
> + depends on SUSPEND && PM_DEBUG && RTC_LIB=y
> + ---help---
> + This option will suspend your machine during bootup, and make
> + it wake up a few seconds later using the RTC's wakeup alarm.
> +
> + You probably want to have your system's RTC driver statically
> + linked, ensuring that it's available when this test runs.
> +
> config SUSPEND_FREEZER
> bool "Enable freezer for suspend to RAM/standby" \
> if ARCH_WANTS_FREEZER_CONTROL || BROKEN
> --- g26.orig/kernel/power/Makefile 2008-02-02 22:30:21.000000000 -0800
> +++ g26/kernel/power/Makefile 2008-02-02 22:37:18.000000000 -0800
> @@ -5,7 +5,7 @@ endif
>
> obj-y := main.o
> obj-$(CONFIG_PM_LEGACY) += pm.o
> -obj-$(CONFIG_PM_SLEEP) += process.o console.o
> +obj-$(CONFIG_PM_SLEEP) += process.o console.o sleepy.o
> obj-$(CONFIG_HIBERNATION) += swsusp.o disk.o snapshot.o swap.o user.o
>
> obj-$(CONFIG_MAGIC_SYSRQ) += poweroff.o
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ g26/kernel/power/sleepy.c 2008-02-02 23:29:53.000000000 -0800
> @@ -0,0 +1,113 @@
> +/*
> + * Copyright (c) 2007 Pavel Machek <pavel@xxxxxxx>
> + * Copyright (c) 2008 David Brownell
> + *
> + * 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"
> +
> +
> +static struct rtc_device *rtc;
> +static suspend_state_t sleepy_state;
> +
> +static int __init has_wakealarm(struct device *dev, void *name_ptr)
> +{
> + struct rtc_device *candidate = to_rtc_device(dev);
> +
> + if (!candidate->ops->set_alarm)
> + return 0;
> + if (!device_may_wakeup(candidate->dev.parent))
> + return 0;
> +
> + *(char **)name_ptr = dev->bus_id;
> + return 1;
> +}
> +
> +#ifdef CONFIG_PM_WAKEALARM_TEST
> +
> +/* This needs to be long enough for the system to suspend all its devices
> + * and enter a suspend-to-RAM (or, potentially, standby) state no matter
> + * what else is going on. But suspending can take arbitrarily long...
> + */
> +#define ALARM_SECONDS 5
> +
> +static void __init test_wakealarm(void)
> +{
> + unsigned long now;
> + struct rtc_wkalrm alm;
> + int status;
> +
> + /* this may fail if the RTC hasn't been initialized */
> + status = rtc_read_time(rtc, &alm.time);
> + if (status < 0) {
> + pr_err("PM: can't read %s time, err %d\n",
> + rtc->dev.bus_id, status);
> + return;
> + }
> + rtc_tm_to_time(&alm.time, &now);
> +
> + memset(&alm, 0, sizeof alm);
> + rtc_time_to_tm(now + ALARM_SECONDS, &alm.time);
> + alm.enabled = true;
> +
> + status = rtc_set_alarm(rtc, &alm);
> + if (status < 0) {
> + pr_err("PM: can't set %s wakealarm, err %d\n",
> + rtc->dev.bus_id, status);
> + return;
> + }
> +
> + pr_info("PM: wakealarm test with Suspend-to-RAM\n");
> + sleepy_state = PM_SUSPEND_MEM;
> + status = pm_suspend(sleepy_state);
> + if (status == -ENODEV) {
> + pr_warning("PM: no Suspend-To-RAM, trying standby...\n");
> + sleepy_state = PM_SUSPEND_STANDBY;
> + status = pm_suspend(sleepy_state);
> + }
> + if (status)
> + pr_err("PM: wakealarm test failed, error %d\n", status);
> +}
> +
> +#else
> +
> +static void __init test_wakealarm(void)
> +{
> + /* FIXME sleepy_state is PM_SUSPEND_ON; not useful ... */
> +}
> +
> +#endif
> +
> +static int __init be_sleepy(void)
> +{
> + char *pony = NULL;
> +
> + class_find_device(rtc_class, &pony, has_wakealarm);
> + if (pony)
> + rtc = rtc_class_open(pony);
> + else
> + pr_warning("PM: no wakealarm-capable RTC driver is ready\n");
> +
> + if (rtc)
> + test_wakealarm();
> + return 0;
> +}
> +late_initcall(be_sleepy);
> --
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--
"Premature optimization is the root of all evil." - Donald Knuth
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