[PATCH 7/8] PM: Make PM_TRACE more architecture independent

Rafael J. Wysocki
2007-11-19T22:40:33Z

From: Johannes Berg <johannes@sipsolutions.net>

When trying to debug a suspend failure I started implementing
PM_TRACE for powerpc. I then noticed that I'm debugging a suspend
failure and so PM_TRACE isn't useful at all, but thought that
nonetheless this could be useful in the future.

Basically, to support PM_TRACE, you add a Kconfig option that
selects PM_TRACE and provides the infrastructure as per the
help text of PM_TRACE.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
drivers/base/power/Makefile | 2 +-
kernel/power/Kconfig | 23 ++++++++++++++++++++++-
2 files changed, 23 insertions(+), 2 deletions(-)

Index: linux-2.6/drivers/base/power/Makefile
===================================================================
--- linux-2.6.orig/drivers/base/power/Makefile
+++ linux-2.6/drivers/base/power/Makefile
@@ -1,7 +1,7 @@
obj-y := shutdown.o
obj-$(CONFIG_PM) += sysfs.o
obj-$(CONFIG_PM_SLEEP) += main.o
-obj-$(CONFIG_PM_TRACE) += trace.o
+obj-$(CONFIG_PM_TRACE_RTC) += trace.o

ifeq ($(CONFIG_DEBUG_DRIVER),y)
EXTRA_CFLAGS += -DDEBUG
Index: linux-2.6/kernel/power/Kconfig
===================================================================
--- linux-2.6.orig/kernel/power/Kconfig
+++ linux-2.6/kernel/power/Kconfig
@@ -44,9 +44,30 @@ config PM_VERBOSE
---help---
This option enables verbose messages from the Power Management code.

+config CAN_PM_TRACE
+ def_bool y
+ depends on PM_DEBUG && PM_SLEEP && EXPERIMENTAL
+
config PM_TRACE
+ bool
+ help
+ This enables code to save the last PM event point across
+ reboot. The architecture needs to support this, x86 for
+ example does by saving things in the RTC, see below.
+
+ The architecture specific code must provide the extern
+ functions from <linux/resume-trace.h> as well as the
+ <asm/resume-trace.h> header with a TRACE_RESUME() macro.
+
+ The way the information is presented is architecture-
+ dependent, x86 will print the information during a
+ late_initcall.
+
+config PM_TRACE_RTC
bool "Suspend/resume event tracing"
- depends on PM_DEBUG && X86 && PM_SLEEP && EXPERIMENTAL
+ depends on CAN_PM_TRACE
+ depends on X86
+ select PM_TRACE
default n
---help---
This enables some cheesy code to save the last PM event point in the