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authorTejun Heo <teheo@suse.de>2009-08-06 18:14:26 +0900
committerTakashi Iwai <tiwai@suse.de>2009-08-10 13:59:36 +0200
commit93fe4483e6fd3e71d17cd919de14b3b1f9eb3795 (patch)
treef147a3fa6b7466c4b02d397091900e3211cd2ef7 /sound/Kconfig
parent0a848680a82e47854347cdfecbe9adf8842719e6 (diff)
downloadlinux-linaro-stable-93fe4483e6fd3e71d17cd919de14b3b1f9eb3795.tar.gz
sound: make OSS device number claiming optional and schedule its removal
If any OSS support is enabled, regardless of built-in or module, sound_core claims full OSS major number (that is, the old 0-255 region) to trap open attempts and request sound modules using custom module aliases. This feature is redundant as chrdev already has such mechanism. This preemptive claiming prevents alternative OSS implementation. The custom module aliases are scheduled to be removed and the previous patch made soundcore emit the standard chrdev aliases too to help transition. This patch schedule the feature for removal in a year and makes it optional so that developers and distros can try new things in the meantime without rebuilding the kernel. The pre-claiming can be turned off by using SOUND_OSS_CORE_PRECLAIM and/or kernel parameter soundcore.preclaim_oss. As this allows sound minors to be individually grabbed by other users, this patch updates sound_insert_unit() such that if registering individual device region fails, it tries the next available slot. For details on removal plan, please read the entry added by this patch in feature-removal-schedule.txt . Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/Kconfig')
-rw-r--r--sound/Kconfig28
1 files changed, 28 insertions, 0 deletions
diff --git a/sound/Kconfig b/sound/Kconfig
index 1eceb85287c5..439e15c8faa3 100644
--- a/sound/Kconfig
+++ b/sound/Kconfig
@@ -32,6 +32,34 @@ config SOUND_OSS_CORE
bool
default n
+config SOUND_OSS_CORE_PRECLAIM
+ bool "Preclaim OSS device numbers"
+ depends on SOUND_OSS_CORE
+ default y
+ help
+ With this option enabled, the kernel will claim all OSS device
+ numbers if any OSS support (native or emulation) is enabled
+ whether the respective module is loaded or not and try to load the
+ appropriate module using sound-slot/service-* and char-major-*
+ module aliases when one of the device numbers is opened. With
+ this option disabled, kernel will only claim actually in-use
+ device numbers and opening a missing device will generate only the
+ standard char-major-* aliases.
+
+ The only visible difference is use of additional module aliases
+ and whether OSS sound devices appear multiple times in
+ /proc/devices. sound-slot/service-* module aliases are scheduled
+ to be removed (ie. PRECLAIM won't be available) and this option is
+ to make the transition easier. This option can be overridden
+ during boot using the kernel parameter soundcore.preclaim_oss.
+
+ Disabling this allows alternative OSS implementations.
+
+ Please read Documentation/feature-removal-schedule.txt for
+ details.
+
+ If unusre, say Y.
+
source "sound/oss/dmasound/Kconfig"
if !M68K