pm: boot time suspend selftest

Boot-time test for system suspend states (STR or standby).  The generic
RTC framework triggers wakeup alarms, which are used to exit those states.

  - Measures some aspects of suspend time ... this uses "jiffies" until
    someone converts it to use a timebase that works properly even while
    timer IRQs are disabled.

  - Triggered by a command line parameter.  By default nothing even
    vaguely troublesome will happen, but "test_suspend=mem" will give
    you a brief STR test during system boot.  (Or you may need to use
    "test_suspend=standby" instead, if your hardware needs that.)

This isn't without problems.  It fires early enough during boot that for
example both PCMCIA and MMC stacks have misbehaved.  The workaround in
those cases was to boot without such media cards inserted.

[matthltc@us.ibm.com: fix compile failure in boot time suspend selftest]
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Pavel Machek <pavel@suse.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 59dfdf1e1d20..dcd165f92a88 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -94,6 +94,17 @@ config SUSPEND
           powered and thus its contents are preserved, such as the
           suspend-to-RAM state (e.g. the ACPI S3 state).
 
+config PM_TEST_SUSPEND
+        bool "Test suspend/resume and wakealarm during bootup"
+        depends on SUSPEND && PM_DEBUG && RTC_LIB=y
+        ---help---
+        This option will let you suspend your machine during bootup, and
+        make it wake up a few seconds later using an RTC wakeup alarm.
+        Enable this with a kernel parameter like "test_suspend=mem".
+
+        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