1 files changed, 20 insertions, 1 deletions

diff --git a/Documentation/sound/alsa/ALSA-Configuration.txt b/Documentation/sound/alsa/ALSA-Configuration.txt
index 8e49c19f6c96..f34821d6d52a 100644
--- a/Documentation/sound/alsa/ALSA-Configuration.txt
+++ b/Documentation/sound/alsa/ALSA-Configuration.txt
@@ -57,7 +57,9 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
                 - Default: 1
                 - For auto-loading more than one card, specify this
                   option together with snd-card-X aliases.
-
+    slots       - Reserve the slot index for the given driver.
+                  This option takes multiple strings.           
+                  See "Module Autoloading Support" section for details.
   
   Module snd-pcm-oss
   ------------------
@@ -2140,6 +2142,23 @@ alias sound-slot-1 snd-ens1371
 In this example, the interwave card is always loaded as the first card
 (index 0) and ens1371 as the second (index 1).
 
+Alternative (and new) way to fixate the slot assignment is to use
+"slots" option of snd module.  In the case above, specify like the
+following: 
+
+options snd slots=snd-interwave,snd-ens1371
+
+Then, the first slot (#0) is reserved for snd-interwave driver, and
+the second (#1) for snd-ens1371.  You can omit index option in each
+driver if slots option is used (although you can still have them at
+the same time as long as they don't conflict).
+
+The slots option is especially useful for avoiding the possible
+hot-plugging and the resultant slot conflict.  For example, in the
+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.
+
 
 ALSA PCM devices to OSS devices mapping
 =======================================