On Mon, Mar 03, 2008 at 03:18:18PM +0100, Pavel Machek wrote:
> Hi!
>
> > diff --git a/include/linux/pm.h b/include/linux/pm.h
> > index 015b735..6e0b9c2 100644
> > --- a/include/linux/pm.h
> > +++ b/include/linux/pm.h
> > @@ -114,6 +114,13 @@ typedef struct pm_message {
> > int event;
> > } pm_message_t;
> >
> > +#ifdef CONFIG_PM
> > +#define pm_call(x) (x)
> > +#else
> > +/* avoid `defined but not used' warning */
> > +#define pm_call(x) ((x) - 1 ? NULL : NULL)
> > +#endif /* CONFIG_PM */
> > +
>
> This is evil. Maybe your gcc is smart enough to optimize this away,
> but I'm not sure mine is.
No problem. Let's use __maybe_unsed then, it gives the same effect.
- - - -
Subject: introduce pm_call() macro to get rid of most #ifdef CONFIG_PM
Currently drivers handle CONFIG_PM this way:
#ifdef CONFIG_PM
drv_suspend() {}
drv_resume() {}
#else
#define drv_suspend NULL
#define drv_resume NULL
#endif
struct driver drv = {
.suspend = drv_suspend,
.resume = drv_resume,
};
With this patch, the code above converts into:
__maybe_unused drv_suspend() {}
__maybe_unused drv_resume() {}
struct driver drv = {
.suspend = pm_call(drv_suspend),
.resume = pm_call(drv_resume),
};
GCC will optimize away suspend/resume calls if they're really
not used.
Signed-off-by: Anton Vorontsov <cbouatmailru@xxxxxxxxx>
---
include/linux/pm.h | 6 ++++++
1 files changed, 6 insertions(+), 0 deletions(-)
diff --git a/include/linux/pm.h b/include/linux/pm.h
index 015b735..a3932c7 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -114,6 +114,12 @@ typedef struct pm_message {
int event;
} pm_message_t;
+#ifdef CONFIG_PM
+#define pm_call(x) (x)
+#else
+#define pm_call(x) NULL
+#endif /* CONFIG_PM */
+
/*
* Several driver power state transitions are externally visible, affecting
* the state of pending I/O queues and (for drivers that touch hardware)
--
1.5.4.3
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