sound: make OSS sound core optional

sound/sound_core.c implements soundcore.ko contains two parts - sound_class which is shared by both ALSA and OSS and device redirection support for OSS. It's always compiled when any sound support is enabled although it's necessary only when OSS (the actual one or emulation) is enabled. This is slightly wasteful and as device redirection always registers character device region for major 14, it prevents alternative implementation.

This patch introduces a new config SOUND_OSS_CORE which is selected iff OSS support is actually necessary and build the OSS core part conditionally.

If OSS is disabled, soundcore merely contains sound_class but leaving it that way seems to be the simplest approach as otherwise sound_class should be in ALSA core file if OSS is disabled but should be in soundcore if OSS is enabled and there's also the user confusion factor.

Signed-off-by Tejun Heo <[email protected]>

sound/sound_core.c +0 -0

+MODULE_ALIAS_CHARDEV_MAJOR(SOUND_MAJOR);

sound/Kconfig menuconfig SOUND · line 35

Quoted 5 lines

sound/Kconfig +4 -0

+config SOUND_OSS_CORE
+	bool
+	default n
+
 source "sound/oss/dmasound/Kconfig"

This seems missing from the scope.
But, I think this should be rather in the block "if SOUND_PRIME" below.

Quoted 2 lines

sound/sound_core.c +0 -0

(snip)

Quoted 1 line

+MODULE_ALIAS_CHARDEV_MAJOR(SOUND_MAJOR);

This alias should be in #ifdef CONFIG_SOUND_OSS_CORE.
The module doesn't provide that major without CONFIG_SOUND_OSS_CORE.

Hello,

Quoted 8 lines · Takashi Iwai

sound/Kconfig menuconfig SOUND · line 35

Quoted 5 lines

sound/Kconfig +4 -0

+config SOUND_OSS_CORE
+	bool
+	default n
+
 source "sound/oss/dmasound/Kconfig"

This seems missing from the scope.
But, I think this should be rather in the block "if SOUND_PRIME" below.

SOUND_OSS_CORE should be turned on if ALSA OSS emul is turned on or arch-um hostsound is turned on, both of which can be enabled regardless of SOUND_PRIME, no?

Quoted 3 lines

SOUND_OSS_CORE should be turned on if ALSA OSS emul is turned on or arch-um hostsound is turned on, both of which can be enabled regardless of SOUND_PRIME, no?

Yes, sorry, I didn't cite clearly. I meant only the last line. sound/oss/dmasound/Kconfig is included and evaluated outside the block "if SOUND_PRIME". Thus, CONFIG_SOUND_OSS_CORE won't be enabled for drivers in sound/oss/dmasound.

My suggestion is to move that line source sound/oss/dmasound/Kconfig into the "if SOUND_PRIME" block first, then apply your patch.

Quoted 8 lines · Takashi Iwai

Quoted 3 lines

SOUND_OSS_CORE should be turned on if ALSA OSS emul is turned on or arch-um hostsound is turned on, both of which can be enabled regardless of SOUND_PRIME, no?

Yes, sorry, I didn't cite clearly. I meant only the last line. sound/oss/dmasound/Kconfig is included and evaluated outside the block "if SOUND_PRIME". Thus, CONFIG_SOUND_OSS_CORE won't be enabled for drivers in sound/oss/dmasound.

Ah.. okay, dmasound also requires SOUND_OSS_CORE but not in SOUND_PRIME. I see.

Quoted 2 lines

My suggestion is to move that line source sound/oss/dmasound/Kconfig into the "if SOUND_PRIME" block first, then apply your patch.

That would pull in sound_firmware. Most likely no big deal but still...

How about just adding select SOUND_OSS_CORE to DMASOUND for
now?

Thanks.

Subject: [PATCH] sound: make OSS sound core optional

sound/sound_core.c implements soundcore.ko and contains two parts - sound_class which is shared by both ALSA and OSS and device redirection support for OSS. It's always compiled when any sound support is enabled although it's necessary only when OSS (the actual one or emulation) is enabled. This is slightly wasteful and as device redirection always registers character device region for major 14, it prevents alternative implementation.

This patch introduces a new config SOUND_OSS_CORE which is selected iff OSS support is actually necessary and build the OSS core part conditionally.

If OSS is disabled, soundcore merely contains sound_class but leaving it that way seems to be the simplest approach as otherwise sound_class should be in ALSA core file if OSS is disabled but should be in soundcore if OSS is enabled. Also, there's also the user confusion factor.

Signed-off-by Tejun Heo <[email protected]>

---
 arch/um/Kconfig.char       |    4 ++
 sound/Kconfig              |    5 ++
 sound/core/Kconfig         |    1 
 sound/oss/dmasound/Kconfig |    1 
 sound/sound_core.c         |   79 ++++++++++++++++++++++++++++++++++-----------
 5 files changed, 71 insertions(+), 19 deletions(-)

Index: work/sound/Kconfig
===================================================================

sound/Kconfig +5 -0

@@ -28,6 +28,10 @@ menuconfig SOUND
 
 if SOUND
 
+config SOUND_OSS_CORE
+	bool
+	default n
+
 source "sound/oss/dmasound/Kconfig"
 
 if !M68K

@@ -80,6 +84,7 @@ endif # SND
 
 menuconfig SOUND_PRIME
 	tristate "Open Sound System (DEPRECATED)"
+	select SOUND_OSS_CORE
 	help
 	  Say 'Y' or 'M' to enable Open Sound System drivers.
 

Index: work/sound/core/Kconfig
===================================================================

sound/core/Kconfig +1 -0

@@ -38,6 +38,7 @@ config SND_SEQ_DUMMY
 	  will be called snd-seq-dummy.
 
 config SND_OSSEMUL
+	select SOUND_OSS_CORE
 	bool
 
 config SND_MIXER_OSS

Index: work/sound/sound_core.c
===================================================================

sound/sound_core.c +60 -19

@@ -1,5 +1,61 @@
 /*
- *	Sound core handling. Breaks out sound functions to submodules
+ *	Sound core.  This file is composed of two parts.  sound_class
+ *	which is common to both OSS and ALSA and OSS sound core which
+ *	is used OSS or emulation of it.
+ */
+
+/*
+ * First, the common part.
+ */
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/err.h>
+
+#ifdef CONFIG_SOUND_OSS_CORE
+static int __init init_oss_soundcore(void);
+static void __exit cleanup_oss_soundcore(void);
+#else
+static inline int init_oss_soundcore(void)	{ return 0; }
+static inline void cleanup_oss_soundcore(void)	{ }
+#endif
+
+struct class *sound_class;
+EXPORT_SYMBOL(sound_class);
+
+MODULE_DESCRIPTION("Core sound module");
+MODULE_AUTHOR("Alan Cox");
+MODULE_LICENSE("GPL");
+
+static int __init init_soundcore(void)
+{
+	int rc;
+
+	rc = init_oss_soundcore();
+	if (rc)
+		return rc;
+
+	sound_class = class_create(THIS_MODULE, "sound");
+	if (IS_ERR(sound_class)) {
+		cleanup_oss_soundcore();
+		return PTR_ERR(sound_class);
+	}
+
+	return 0;
+}
+
+static void __exit cleanup_soundcore(void)
+{
+	cleanup_oss_soundcore();
+	class_destroy(sound_class);
+}
+
+module_init(init_soundcore);
+module_exit(cleanup_soundcore);
+
+
+#ifdef CONFIG_SOUND_OSS_CORE
+/*
+ *	OSS sound core handling. Breaks out sound functions to submodules
  *	
  *	Author:		Alan Cox <[email protected]>
  *

@@ -34,21 +90,17 @@
  *	locking at some point in 2.3.x.
  */
 
-#include <linux/module.h>
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/smp_lock.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
-#include <linux/fs.h>
 #include <linux/sound.h>
 #include <linux/major.h>
 #include <linux/kmod.h>
-#include <linux/device.h>
 
 #define SOUND_STEP 16
 
-
 struct sound_unit
 {
 	int unit_minor;

@@ -64,9 +116,6 @@ extern int msnd_classic_init(void);
 extern int msnd_pinnacle_init(void);
 #endif
 
-struct class *sound_class;
-EXPORT_SYMBOL(sound_class);
-
 /*
  *	Low level list operator. Scan the ordered list, find a hole and
  *	join into it. Called with the lock asserted

@@ -523,31 +572,23 @@ int soundcore_open(struct inode *inode,
 	return -ENODEV;
 }
 
-MODULE_DESCRIPTION("Core sound module");
-MODULE_AUTHOR("Alan Cox");
-MODULE_LICENSE("GPL");
 MODULE_ALIAS_CHARDEV_MAJOR(SOUND_MAJOR);
 
-static void __exit cleanup_soundcore(void)
+static void __exit cleanup_oss_soundcore(void)
 {
 	/* We have nothing to really do here - we know the lists must be
 	   empty */
 	unregister_chrdev(SOUND_MAJOR, "sound");
-	class_destroy(sound_class);
 }
 
-static int __init init_soundcore(void)
+static int __init init_oss_soundcore(void)
 {
 	if (register_chrdev(SOUND_MAJOR, "sound", &soundcore_fops)==-1) {
 		printk(KERN_ERR "soundcore: sound device already in use.\n");
 		return -EBUSY;
 	}
-	sound_class = class_create(THIS_MODULE, "sound");
-	if (IS_ERR(sound_class))
-		return PTR_ERR(sound_class);
 
 	return 0;
 }
 
-module_init(init_soundcore);
-module_exit(cleanup_soundcore);
+#endif /* CONFIG_SOUND_OSS_CORE */

Index: work/arch/um/Kconfig.char
===================================================================

arch/um/Kconfig.char +4 -0

@@ -203,6 +203,10 @@ config SOUND
 	tristate
 	default UML_SOUND
 
+config SOUND_OSS_CORE
+	bool
+	default UML_SOUND
+
 config HOSTAUDIO
 	tristate
 	default UML_SOUND

Index: work/sound/oss/dmasound/Kconfig
===================================================================

sound/oss/dmasound/Kconfig +1 -0

@@ -42,3 +42,4 @@ config DMASOUND_Q40
 
 config DMASOUND
 	tristate
+	select SOUND_OSS_CORE