Re: [PATCH] acpi: fix pwr_btn_event_pending build error

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Sunday, July 22, 2012, Paul E. McKenney wrote:
> On Sun, Jul 22, 2012 at 03:08:40AM +0300, Kirill A. Shutemov wrote:
> > On Sat, Jul 21, 2012 at 04:37:14PM -0700, Paul E. McKenney wrote:
> > > On Sun, Jul 22, 2012 at 12:52:43AM +0300, Kirill A. Shutemov wrote:
> > > > On Sat, Jul 21, 2012 at 02:41:56PM -0700, Paul E. McKenney wrote:
> > > > > Hello!
> > > > > 
> > > > > A recent build for KVM on x86 resulted in the following build error:
> > > > > 
> > > > > drivers/acpi/sleep.c:60:13: warning: ‘pwr_btn_event_pending’ defined but not
> > > > > +used [-Wunused-variable]
> > > > > 
> > > > > This patch silences this error.
> > > > > 
> > > > > Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
> > > > > 
> > > > > diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
> > > > > index 8856102..18347aa 100644
> > > > > --- a/drivers/acpi/sleep.c
> > > > > +++ b/drivers/acpi/sleep.c
> > > > > @@ -57,7 +57,9 @@ MODULE_PARM_DESC(gts, "Enable evaluation of _GTS on suspend.");
> > > > >  MODULE_PARM_DESC(bfs, "Enable evaluation of _BFS on resume".);
> > > > >  
> > > > >  static u8 sleep_states[ACPI_S_STATE_COUNT];
> > > > > +#ifdef CONFIG_ACPI_SLEEP
> > > > >  static bool pwr_btn_event_pending;
> > > > > +#endif /* #ifdef CONFIG_ACPI_SLEEP */
> > > > 
> > > > __maybe_unused ?
> > > 
> > > Are the compiler and linker smart enough to get rid of the storage in
> > > case it really isn't used?  (Not that the storage for a bool is worth
> > > worrying about, but...)
> > 
> > GCC with optimization enabled will get rid of the storage even without
> > __maybe_unused.
> 
> OK, that should allow me to get rid of a few ifdefs, then!  For this one,
> please see below.
> 
> 							Thanx, Paul
> 
> ------------------------------------------------------------------------
> 
> acpi: fix pwr_btn_event_pending build error
> 
> A recent build for KVM on x86 resulted in the following build error:
> 
> drivers/acpi/sleep.c:60:13: warning: ‘pwr_btn_event_pending’ defined but not
> +used [-Wunused-variable]
> 
> This patch silences this error.
> 
> Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>

Well, I prefer the one below.

Thanks,
Rafael

---
From: Rafael J. Wysocki <rjw@sisk.pl>
Subject: ACPI / PM: Fix build warning in sleep.c for CONFIG_ACPI_SLEEP unset

If CONFIG_ACPI_SLEEP is unset, the compiler complains that
pwr_btn_event_pending is defined but not used.  To silence the
warning, move the definition of pwr_btn_event_pending under an
apprporiate #ifdef.

Reported-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 drivers/acpi/sleep.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux/drivers/acpi/sleep.c
===================================================================
--- linux.orig/drivers/acpi/sleep.c
+++ linux/drivers/acpi/sleep.c
@@ -57,7 +57,6 @@ MODULE_PARM_DESC(gts, "Enable evaluation
 MODULE_PARM_DESC(bfs, "Enable evaluation of _BFS on resume".);
 
 static u8 sleep_states[ACPI_S_STATE_COUNT];
-static bool pwr_btn_event_pending;
 
 static void acpi_sleep_tts_switch(u32 acpi_state)
 {
@@ -110,6 +109,7 @@ static int acpi_sleep_prepare(u32 acpi_s
 
 #ifdef CONFIG_ACPI_SLEEP
 static u32 acpi_target_sleep_state = ACPI_STATE_S0;
+static bool pwr_btn_event_pending;
 
 /*
  * The ACPI specification wants us to save NVS memory regions during hibernation