[PATCH 8/8] ALSA: doc: Explain more about model option

[Takashi Iwai]

Add a bit more explanation about passing the snd-hda-intel model
option at the right place.  Also, a brief description about the new
codec model option is added along with it.

Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
 Documentation/sound/hd-audio/notes.rst | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/Documentation/sound/hd-audio/notes.rst b/Documentation/sound/hd-audio/notes.rst
index d118b6fe269b..dc84be14273b 100644
--- a/Documentation/sound/hd-audio/notes.rst
+++ b/Documentation/sound/hd-audio/notes.rst
@@ -226,6 +226,22 @@ model=103c:8862 will apply the quirk for HP ProBook 445 G8 (which
 isn't found in the model table as of writing) as long as the device is
 handled equivalently by the same driver.
 
+The ``model`` option of snd-hda-intel takes an array of strings,
+applied one per PCI device.  When there are multiple HD-audio
+controllers and you want to apply a quirk for a certain one, you have
+to pass the option carefully at the right position.
+For example, when an on-board analog audio with a Realtek codec is
+found at the secondary PCI slot while the first slot is for HDMI/DP
+controller, you'll need to pass the option like ``model=,foobar``
+(note the comma before ``foobar``), so that the first entry is
+skipped.
+
+For making this complexity a bit easier, since 6.1 kernel, codec
+drivers may take also ``model`` option, too. It works equivalently as
+the model option of the controller driver.
+In the example case above, you can pass the option to Realtek codec
+driver directly; e.g. ``snd_hda_codec_realtek.model=foobar`` on
+command line.
 
 Speaker and Headphone Output
 ----------------------------
-- 
2.35.3