[PATCH] staging: greybus: mark PM functions as __maybe_unused

[PATCH] staging: greybus: mark PM functions as __maybe_unused

[Arnd Bergmann]

Enabling the arche platform for compile testing showed a harmless
warning with CONFIG_PM=n:

drivers/staging/greybus/arche-platform.c:632:12: error: 'arche_platform_resume' defined but not used [-Werror=unused-function]
drivers/staging/greybus/arche-platform.c:618:12: error: 'arche_platform_suspend' defined but not used [-Werror=unused-function]

This marks the functions as __maybe_unused to shut up the warnings.

Fixes: 2eccd4aa19fc ("staging: greybus: enable compile testing of arche driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/staging/greybus/arche-platform.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/greybus/arche-platform.c b/drivers/staging/greybus/arche-platform.c
index 5bce5e039596..eced2d26467b 100644
--- a/drivers/staging/greybus/arche-platform.c
+++ b/drivers/staging/greybus/arche-platform.c
@@ -615,7 +615,7 @@ static int arche_platform_remove(struct platform_device *pdev)
 	return 0;
 }
 
-static int arche_platform_suspend(struct device *dev)
+static __maybe_unused int arche_platform_suspend(struct device *dev)
 {
 	/*
 	 * If timing profile premits, we may shutdown bridge
@@ -629,7 +629,7 @@ static int arche_platform_suspend(struct device *dev)
 	return 0;
 }
 
-static int arche_platform_resume(struct device *dev)
+static __maybe_unused int arche_platform_resume(struct device *dev)
 {
 	/*
 	 * Atleast for ES2 we have to meet the delay requirement between
-- 
2.9.0

Re: [PATCH] staging: greybus: mark PM functions as __maybe_unused

[Johan Hovold]

On Thu, May 18, 2017 at 03:28:00PM +0200, Arnd Bergmann wrote:
> Enabling the arche platform for compile testing showed a harmless
> warning with CONFIG_PM=n:
> 
> drivers/staging/greybus/arche-platform.c:632:12: error: 'arche_platform_resume' defined but not used [-Werror=unused-function]
> drivers/staging/greybus/arche-platform.c:618:12: error: 'arche_platform_suspend' defined but not used [-Werror=unused-function]
> 
> This marks the functions as __maybe_unused to shut up the warnings.
> 
> Fixes: 2eccd4aa19fc ("staging: greybus: enable compile testing of arche driver")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Acked-by: Johan Hovold <johan@kernel.org>

Thanks for fixing this.

Johan

Re: [greybus-dev] [PATCH] staging: greybus: mark PM functions as __maybe_unused

[Viresh Kumar]

On 18-05-17, 15:28, Arnd Bergmann wrote:
> Enabling the arche platform for compile testing showed a harmless
> warning with CONFIG_PM=n:
> 
> drivers/staging/greybus/arche-platform.c:632:12: error: 'arche_platform_resume' defined but not used [-Werror=unused-function]
> drivers/staging/greybus/arche-platform.c:618:12: error: 'arche_platform_suspend' defined but not used [-Werror=unused-function]
> 
> This marks the functions as __maybe_unused to shut up the warnings.
> 
> Fixes: 2eccd4aa19fc ("staging: greybus: enable compile testing of arche driver")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/staging/greybus/arche-platform.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/staging/greybus/arche-platform.c b/drivers/staging/greybus/arche-platform.c
> index 5bce5e039596..eced2d26467b 100644
> --- a/drivers/staging/greybus/arche-platform.c
> +++ b/drivers/staging/greybus/arche-platform.c
> @@ -615,7 +615,7 @@ static int arche_platform_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> -static int arche_platform_suspend(struct device *dev)
> +static __maybe_unused int arche_platform_suspend(struct device *dev)
>  {
>  	/*
>  	 * If timing profile premits, we may shutdown bridge
> @@ -629,7 +629,7 @@ static int arche_platform_suspend(struct device *dev)
>  	return 0;
>  }
>  
> -static int arche_platform_resume(struct device *dev)
> +static __maybe_unused int arche_platform_resume(struct device *dev)
>  {
>  	/*
>  	 * Atleast for ES2 we have to meet the delay requirement between

Is __maybe_unused the more preferred way than putting these routines
under CONFIG_PM_SLEEP ifdef ?

-- 
viresh

Re: [greybus-dev] [PATCH] staging: greybus: mark PM functions as __maybe_unused

[Arnd Bergmann]

On Thu, May 18, 2017 at 4:18 PM, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> On 18-05-17, 15:28, Arnd Bergmann wrote:
>> Enabling the arche platform for compile testing showed a harmless
>> warning with CONFIG_PM=n:
>>
>> drivers/staging/greybus/arche-platform.c:632:12: error: 'arche_platform_resume' defined but not used [-Werror=unused-function]
>> drivers/staging/greybus/arche-platform.c:618:12: error: 'arche_platform_suspend' defined but not used [-Werror=unused-function]
>>
>> This marks the functions as __maybe_unused to shut up the warnings.
>>
>> Fixes: 2eccd4aa19fc ("staging: greybus: enable compile testing of arche driver")
>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>> ---
>>  drivers/staging/greybus/arche-platform.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/staging/greybus/arche-platform.c b/drivers/staging/greybus/arche-platform.c
>> index 5bce5e039596..eced2d26467b 100644
>> --- a/drivers/staging/greybus/arche-platform.c
>> +++ b/drivers/staging/greybus/arche-platform.c
>> @@ -615,7 +615,7 @@ static int arche_platform_remove(struct platform_device *pdev)
>>       return 0;
>>  }
>>
>> -static int arche_platform_suspend(struct device *dev)
>> +static __maybe_unused int arche_platform_suspend(struct device *dev)
>>  {
>>       /*
>>        * If timing profile premits, we may shutdown bridge
>> @@ -629,7 +629,7 @@ static int arche_platform_suspend(struct device *dev)
>>       return 0;
>>  }
>>
>> -static int arche_platform_resume(struct device *dev)
>> +static __maybe_unused int arche_platform_resume(struct device *dev)
>>  {
>>       /*
>>        * Atleast for ES2 we have to meet the delay requirement between
>
> Is __maybe_unused the more preferred way than putting these routines
> under CONFIG_PM_SLEEP ifdef ?

I find that a lot of users get the #ifdef wrong, either using the wrong
macro (CONFIG_PM vs CONFIG_PM_SLEEP) or not using the right
set of functions (e.g. calling a function only from the suspend handler).

The __maybe_unused annotation avoids both problems and also gives
better build time coverage, so that's what I tend to use.

     Arnd

Re: [greybus-dev] [PATCH] staging: greybus: mark PM functions as __maybe_unused

[Viresh Kumar]

On 18-05-17, 16:51, Arnd Bergmann wrote:
> I find that a lot of users get the #ifdef wrong, either using the wrong
> macro (CONFIG_PM vs CONFIG_PM_SLEEP) or not using the right
> set of functions (e.g. calling a function only from the suspend handler).
> 
> The __maybe_unused annotation avoids both problems and also gives
> better build time coverage, so that's what I tend to use.

Thanks for the explanation Arnd. I hope these unused routines will not
be part of the binary that gets generated. Right?

Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>

-- 
viresh

Re: [greybus-dev] [PATCH] staging: greybus: mark PM functions as __maybe_unused

[Arnd Bergmann]

On Fri, May 19, 2017 at 5:40 AM, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> On 18-05-17, 16:51, Arnd Bergmann wrote:
>> I find that a lot of users get the #ifdef wrong, either using the wrong
>> macro (CONFIG_PM vs CONFIG_PM_SLEEP) or not using the right
>> set of functions (e.g. calling a function only from the suspend handler).
>>
>> The __maybe_unused annotation avoids both problems and also gives
>> better build time coverage, so that's what I tend to use.
>
> Thanks for the explanation Arnd. I hope these unused routines will not
> be part of the binary that gets generated. Right?

Correct. Ancient compilers (gcc-4.1) had a bug where a function would
still be part of the binary if the only reference to it was from a function
pointer that got dropped through dead code elimination, but that is not
the case here, and those old compilers are not used in real life any more
either.

       Arnd