[PATCH] sound: Added missing conditionnal for OSS function prototypes

[PATCH] sound: Added missing conditionnal for OSS function prototypes

[Nicholas Niro]

As per the source file sound/sound_core.c, the function prototypes
register_sound_special, register_sound_special_device et al, are
all prototypes that are only compiled when the flag
CONFIG_SOUND_OSS_CORE is set. But regardless of if
it is set, those prototypes are still all
available in linux/sound.h.

This bug was found when trying to compile standalone alsa.
In order to check for the function register_sound_special_device
availability, it looks for it's prototype in linux/sound.h and of course
it finds it because of the bug (even if it's not, actually, compiled in),
creating unknown symbol errors when loading snd.ko et al.

Signed-off-by: Nicholas Niro <nik_89@neuroponic.com>
Cc: Takashi Iwai <tiwai@suse.de>
---
 include/linux/sound.h |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/include/linux/sound.h b/include/linux/sound.h
index 44dcf05..7e49712 100644
--- a/include/linux/sound.h
+++ b/include/linux/sound.h
@@ -30,6 +30,7 @@
  *	Sound core interface functions
  */
  
+#ifdef CONFIG_SOUND_OSS_CORE
 struct device;
 extern int register_sound_special(const struct file_operations *fops, int unit);
 extern int register_sound_special_device(const struct file_operations *fops, int unit, struct device *dev);
@@ -41,4 +42,5 @@ extern void unregister_sound_special(int unit);
 extern void unregister_sound_mixer(int unit);
 extern void unregister_sound_midi(int unit);
 extern void unregister_sound_dsp(int unit);
+#endif /* CONFIG_SOUND_OSS_CORE */
 #endif /* __KERNEL__ */
-- 
1.7.4.1.107.g394f

Re: [PATCH] sound: Added missing conditionnal for OSS function prototypes

[Takashi Iwai]

At Sat, 05 Mar 2011 01:07:52 -0500,
Nicholas Niro wrote:
> 
> As per the source file sound/sound_core.c, the function prototypes
> register_sound_special, register_sound_special_device et al, are
> all prototypes that are only compiled when the flag
> CONFIG_SOUND_OSS_CORE is set. But regardless of if
> it is set, those prototypes are still all
> available in linux/sound.h.

Well, the conventional way for such a case is to define dummy functions
with static inline.

> This bug was found when trying to compile standalone alsa.
> In order to check for the function register_sound_special_device
> availability, it looks for it's prototype in linux/sound.h and of course
> it finds it because of the bug (even if it's not, actually, compiled in),
> creating unknown symbol errors when loading snd.ko et al.

I don't think it's worth to patch such a deadly old and almost
deprecated file just for the builds of external module tree.
It's basically a problem of alsa-driver external build system (likely
it wrongly detects CONFIG_SND_OSSEMUL).  This is the thing to be fixed.


thanks,

Takashi

> ---
>  include/linux/sound.h |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/include/linux/sound.h b/include/linux/sound.h
> index 44dcf05..7e49712 100644
> --- a/include/linux/sound.h
> +++ b/include/linux/sound.h
> @@ -30,6 +30,7 @@
>   *	Sound core interface functions
>   */
>   
> +#ifdef CONFIG_SOUND_OSS_CORE
>  struct device;
>  extern int register_sound_special(const struct file_operations *fops, int unit);
>  extern int register_sound_special_device(const struct file_operations *fops, int unit, struct device *dev);
> @@ -41,4 +42,5 @@ extern void unregister_sound_special(int unit);
>  extern void unregister_sound_mixer(int unit);
>  extern void unregister_sound_midi(int unit);
>  extern void unregister_sound_dsp(int unit);
> +#endif /* CONFIG_SOUND_OSS_CORE */
>  #endif /* __KERNEL__ */
> -- 
> 1.7.4.1.107.g394f
>