[ALSA] Improve the slots option handling

Fix and improve the slots option handling.  The sound core tries to
find the slot with the given module name first and assign if it's
still available.  If all pre-given slots are unavailable, then try
to find another free slot.

Also, when a module name begins with '!', it means the negative match:
the slot will be given for any modules but that one.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 4 insertions, 0 deletions

diff --git a/Documentation/sound/alsa/ALSA-Configuration.txt b/Documentation/sound/alsa/ALSA-Configuration.txt
index f48939e97aba..529073dea196 100644
--- a/Documentation/sound/alsa/ALSA-Configuration.txt
+++ b/Documentation/sound/alsa/ALSA-Configuration.txt
@@ -2271,6 +2271,10 @@ case above again, the first two slots are already reserved.  If any
 other driver (e.g. snd-usb-audio) is loaded before snd-interwave or
 snd-ens1371, it will be assigned to the third or later slot.
 
+When a module name is given with '!', the slot will be given for any
+modules but that name.  For example, "slots=!snd-pcsp" will reserve
+the first slot for any modules but snd-pcsp. 
+
 
 ALSA PCM devices to OSS devices mapping
 =======================================