ALSA: hda - More description about patch module option
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/Documentation/sound/alsa/HD-Audio.txt b/Documentation/sound/alsa/HD-Audio.txt
index 8bc9867..55aab11 100644
--- a/Documentation/sound/alsa/HD-Audio.txt
+++ b/Documentation/sound/alsa/HD-Audio.txt
@@ -410,7 +410,7 @@
codec. This can work basically like the reconfiguration via sysfs in
the above, but it does it before the first codec configuration.
-The patch file looks like below:
+A patch file is a plain text file which looks like below:
------------------------------------------------------------------------
[codec]
@@ -448,6 +448,20 @@
sysfs entries, and the lines after `[hint]` are parsed as `hints`
sysfs entries, respectively.
+The hd-audio driver reads the file via request_firmware(). Thus,
+a patch file has to be located on the appropriate firmware path,
+typically, /lib/firmware. For example, when you pass the option
+`patch=hda-init.fw`, the file /lib/firmware/hda-init-fw must be
+present.
+
+The patch module option is specific to each card instance, and you
+need to give one file name for each instance, separated by commas.
+For example, if you have two cards, one for an on-board analog and one
+for an HDMI video board, you may pass patch option like below:
+------------------------------------------------------------------------
+ options snd-hda-intel patch=on-board-patch,hdmi-patch
+------------------------------------------------------------------------
+
Power-Saving
~~~~~~~~~~~~