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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 /Documentation
parent0a848680a82e47854347cdfecbe9adf8842719e6 (diff)
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 'Documentation')
-rw-r--r--Documentation/feature-removal-schedule.txt24
1 files changed, 24 insertions, 0 deletions
diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index 09e031c5588..f0690bbbd73 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -468,3 +468,27 @@ Why: cpu_policy_rwsem has a new cleaner definition making it local to
cpufreq core and contained inside cpufreq.c. Other dependent
drivers should not use it in order to safely avoid lockdep issues.
Who: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
+
+----------------------------
+
+What: sound-slot/service-* module aliases and related clutters in
+ sound/sound_core.c
+When: August 2010
+Why: OSS sound_core grabs all legacy minors (0-255) of SOUND_MAJOR
+ (14) and requests modules using custom sound-slot/service-*
+ module aliases. The only benefit of doing this is allowing
+ use of custom module aliases which might as well be considered
+ a bug at this point. This preemptive claiming prevents
+ alternative OSS implementations.
+
+ Till the feature is removed, the kernel will be requesting
+ both sound-slot/service-* and the standard char-major-* module
+ aliases and allow turning off the pre-claiming selectively via
+ CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss
+ kernel parameter.
+
+ After the transition phase is complete, both the custom module
+ aliases and switches to disable it will go away. This removal
+ will also allow making ALSA OSS emulation independent of
+ sound_core. The dependency will be broken then too.
+Who: Tejun Heo <tj@kernel.org>