HD-AUDIO EMULATOR
			=================

GENERAL
-------

hda-emu ("HD-Audio EMUlator", or "Horribly Destructive And
Embarrassingly Malfunctional Unit") is a program written for making
test and debug of ALSA HD-audio driver easier.  The source tree
contains three things: the HD-audio controller/codec emulation codes,
the build stub for codec parser codes in the kernel HD-audio driver
tree, and a collection of codec proc files.

This package itself doesn't contain the kernel driver code at all.
You need to prepare the Linux kernel-tree to emulate, and pass the
root directory of Linux kernel to --with-kerneldir option of configure
script.  For example, if you have linux-4.0 kernel in
/somewhere/linux-4.0,

	% ./configure --with-kerneldir=/somewhere/linux-2.0

Then it'll copy (symlink) the files from the given directory into
kernel subdirectory.

The wrapper of kernel functions can be found in include directory.
There are several cheats and tricks there.  Many codes are replaced
with other normal functions.

The build is as usual -- configure and make.  No special requirement,
as far as I know.


GETTING STARTED
---------------

Start hda-emu program with a codec proc file to emulate.

	% hda-emu my-proc-file

The program will skip other lines than proc contents, so you can pass
alsa-info.sh output, too.  If the file contains multiple codecs, you
can specify the codec index via -i option.  As default, the first
codec is used.

	% hda-emu -i 1 alsa-info.txt

For testing, just pick up one file found in codecs subdirectory.

As default, the program is pretty verbose.  When you start it up,
you'll see a bunch of messages like:

	% hda-emu codecs/stac9200-dell-d820-laptop

# Parsing..
hda_codec: Unknown model for STAC9200, using BIOS defaults
hda_codec: pin nid 08 bios pin config 40c003fa
...

The emulator prints all logs of snd_printdd() and snd_printd() in the
default log level in addition to its own messages.  To suppress the
driver log messages, pass -l option with an appropriate log level.
The level 0 will suppress all messages except for errors.
The level 1 will show snd_printd() and snd_printdd() messages as well
as basic messages of hda-emu itself.
The level 2 will show each codec verbs in addition to messages shown
via the level 1.

The program has a stupid dumb command shell, and will ask you a command
after initializing and showing the messages.

	# Building controls...
	CTRL: add: Master Playback Volume:0
	...
	# Building PCMs...
	> 

At this point, you can give a command.  For example, type "help" or
"h" and enter,

	> help
	Available commands: list get set dump jack option help verb pm \
	init fs quit
	Run "help CMD" for details

No surprise, huh?

The basic commands are described in the next sections.


BASIC COMMANDS
--------------

* list

  List the control (mixer) elements created by the driver.

	> list
	1: Master Playback Volume:0 (1)
	2: Master Playback Switch:0 (1)
	3: Input Source:0 (1)
	4: Capture Volume:0 (1)
	...

  The first number is the control element numid.  This number is used
  in get and set commands to specify the element. 
  Then the control element name follows.  The number after colon (:)
  shows the element index.  When multiple elements with the same name
  exists, there can be more than zero there. 
  The last number in parentheses is the number of multi-elements.
  When this is more than 1, it means that there are multiple elements.

* get

  Get the control element information.  Pass the numid of the element
  to see.

	> get 1
	1 Master Playback Volume:0
	MIN/MAX: 0/31,  VAL: [0] [0]

  In this case, the element 1, "Master Playback Volume", takes an
  integer value between 0 and 31, and its current values are 0 and 0
  (usually for left and right channels).

  Instead of the numid, you can pass the name string of the control
  element.  Use single- or double quotes around the name.

	> get "Master Playback Volume"
	1 Master Playback Volume:0
	MIN/MAX: 0/31,  VAL: [0] [0]

  If there are multiple control elements with the same name and
  different indices, pass the index number with ":" suffix.

	> get "Headphone Playback Switch:1"
	20 Headphone Playback Switch:1
	MIN/MAX: 0/1,  VAL: [1] [1]


* set

  Set the control element value.  Pass the numid or the name string in
  the first argument, and pass and the value(s) in the rest.

	> set 1 10 4

  or

	> set "Master Playback Volume" 10 4

  When the log level is more than 1, you'll see the codec verbs such
  as

	send: NID=0xb, VERB=0x3a0(set_amp_gain_mute), PARM=0xa
	send: NID=0xb, VERB=0x390(set_amp_gain_mute), PARM=0x84

* dump

  Dump the codec proc output.  This is identical with proc file
  contents.

	> dump
	Codec: SigmaTel STAC9200
	Address: 0
	Vendor Id: 0x83847690
	Subsystem Id: 0x102801cc
	...

  If you would like to show only a certain widget, you can pass the
  widget NID as the argument.

	> dump 0x10
	Node 0x10 [Pin Complex] wcaps 0x400181: Stereo
	  Pincap 0x081737: IN OUT
	  Pin Default 0x01a19021: [Jack] Mic at Ext Rear
	    Conn = 1/8, Color = Pink
	  Pin-ctls: 0x20: IN
	  Connection: 1

  Passing the value 0 to the first argument is equivalent without
  passing the argument, i.e. showing full dump.
  By passing the value 1, it dumps only the codec and FG information
  (e.g. codec name, vendor id, etc).

  Also, you can pass a file name to the second argument if you want
  to save the dump to the specifid file.

* jack

  Get / set the jack plug state.  When invoked without arguments,
  it lists the active pin NIDs.

	> jack
	NID 0x0d: cfg 0x032110f0: [Jack] HP Out at Ext Left
	NID 0x0f: cfg 0x03a110f0: [Jack] Mic at Ext Left
	NID 0x10: cfg 0x921701f0: [Fixed] Speaker at Int Front
	NID 0x11: cfg 0x95a601f0: [Fixed] Mic at Int Top

  Usually this shows the jack status the driver keeps internally.
  If you'd need to look at the original default pincfg, pass -r
  option.

	> jack -r
	NID 0x0d: cfg 0x921701f0: [Fixed] Speaker at Int Front
	...
  (Note that the difference appears only with 3.8 or later kernel
   code.  In the older kernels, both results with and without -r
   will show the same list.)

  When called with a widget numid, it shows the current jack state.

	> jack 0x0d
	Jack state [0xd] = 0

  To emulate the jack plug / unplug, set the value in the second
  argument, either 1 or 0.  With the loglevel > 1, you'll see the
  codec verbs handled in the unsol_event handler.

	> jack 0x0d 1
	send: NID=0xd, VERB=0xf09(get_pin_sense), PARM=0x0
	receive: 0x80000000
	send: NID=0xd, VERB=0x707(set_pin_ctl), PARM=0xc0
	...

* PCM

  List the registered PCM streams or test the PCM stream.
  When no argument is passed, hda-emu lists the all registered PCM
  streams.  For example,

	> PCM
	0: STAC92xx Analog:0 (audio), play=1, capt=2
	1: STAC92xx Digital:1 (SPDIF), play=1, capt=0

  where the first number indicates the stream ID number.

  For testing a PCM stream, pass the ID number to the first argument,
  and the stream direction, either playback or capture (or 0, 1).
  Also, pass the sample rate (default = 48000), channels (default =
  2), and format bits (default = 16) if you want to test with
  different values.  Then hda-emu does a single-shot PCM test: open,
  prepare, cleanup and close.

	> PCM 0 p 48000 2 16
	Open PCM STAC92xx Analog for play
	send: NID=0x21, VERB=0xf00(get_parameters), PARM=0xa(PCM)
	receive: 0xe07e0
	...
	Prepare PCM, rate=48000, channels=2, format=16 bits
	PCM format_val = 0x11
	...

  A PCM substream can be specified as a style of "a:b".  For example,
  passing 1:2 for the first argument means that the stream id 1, the
  substream id 2.  This is useful to check when the driver supports
  the multiple-substreams.
  
  As default, PCM command simulates from open to close.  When -s
  option is passed after "PCM", it operates only the open/prepare.
  When -e option is passed, it operates only the close procedure.

* route

  Show the routes from/to the given widget.

	> route 0x28
	Pin[2c] -- Mix[21] -- Mix[1b] -> Pin[28]
	Out[08] -> Sel[34] -- Mix[1b] -> Pin[28]
	
	Pin[28] -- Mix[21] -- Mix[1c] -> Pin[29]
	Pin[28] -- Mix[21] -- Mix[1b] -> Pin[28]
	...

  When -x option is passed, it shows also the routes from/to inactive
  pins.

  As default, it shows only the active (i.e. currently connected)
  routes.  When option -a is passed before the widget NID, it shows
  all routes even though the connection isn't active.  (-a option
  includes -i option implicitly.)

	> route -a 0x28
	Pin[2c] -- Mix[21] -- Mix[1b] -> Pin[28]
	Out[08] -> Sel[34] -- Mix[1b] -> Pin[28]

	Pin[28] -- Mix[21] -x Sel[1f] -> In [11]
	Pin[28] -- Mix[21] -x Sel[1e] -> In [10]
	Pin[28] -- Mix[21] -- Mix[1c] -> Pin[29]
	Pin[28] -- Mix[21] -- Mix[1b] -> Pin[28]
	...

  The options -i and -o specify the direction of connection.  When -i
  is passed, it shows only the routes ended to the given NID. When -o
  is passed, shows only the routes starting from the given NID.  As
  default, both routes are shown.

  The option -m makes the mute flag appearing in the routes.  When
  an input or an output amp is muted, the letter '|' appears in the
  path.

* pm

  Simulate suspend/resume cycle.

  When option -i is given, the pin control values and the in/out amp
  values are reset to the initial state before resume.  When option -r
  is given, the pin control values and the in/out amp values are set
  randomly before resume.  These options are useful to check whether
  the resume procedure properly restores the values.

* quit

  Quit the shell.


ADVANCED COMMANDS
-----------------

* verb

  Execute a verb.  Use as you like.

	> verb 0x0d 0xf07 0x00
	Command response:: 0xc0

* unsol

  Issue an arbitrary unsolicited event.  Pass the NID to issue an
  event.  The tag is automatically obtained from the current widget
  status.

* option

  Change the module option dynamically.
  Currently, only power_save option can be changed by this command.

	> option power_save
	Power-save = 0

	> option power_save 1

	> option power_save
	Power-save = 1

* fs

  Access to sysfs file entry.  This command takes a sub-command,
  either of "get", "set" and "list".  Not all sysfs files are
  available yet.

  "fs list" shows the available sysfs file entries.

	> fs list
	Available sysfs entries:
	  driver_pin_configs (R)
	  init_pin_configs (R)
	  ...

	> fs get init_pin_configs
	0x24 0x01014010
	0x25 0x01011012
	0x26 0x01016011
	...

	> fs set user_pin_configs 0x24 0x411111f0
	send: NID=0x24, VERB=0x71c(set_config_def_0), PARM=0xf0
	...

	> fs set hints jack_detect=false

	> fs get hints
	jack_detect = false

	> fs set reconfig 1


LOG FILE
--------

The messages can be saved to a file by starting with -o option.
When -q option is given, the program doesn't echo the messages to
stdout but outputs only to the log file.  It's useful for automating
test.  The shell command can be fed from stdin, so you can write a
command sequence in a file and redirect it to hda-emu.


MODEL OPTION
------------

If you need to give a certain "model" module option to the driver,
e.g. if you need to debug the behavior of the driver with
model=laptop, pass it via -m option to hda-emu.  Also, the PCI SSID
can be overridden by -p option.


COLORED OUTPUT
--------------

As default, hda-emu outputs the lines in color using ANSI escape
sequences.  The escape sequences will be stripped in the log files,
though.  You can toggle color/non-color behavior via -C and -M
options, respectively.


INITIAL PIN-CONFIGURATION AND HINTS
-----------------------------------

As default, hda-emu takes the default pin-configurations as set in the
given codec proc file (or the proc file content in the given
alsa-info.sh output).  But the codec proc file might contain the
status that is already overwritten by the driver or changed by user,
which isn't identical with the real initial state.

When the pin-config sysfs file is available, hda-emu can read it and
initialize the pin defaults accordingly via -P option.  When the input
file is a recent alsa-info.sh output containing sysfs file entries,
pass like "-P hwC0D0/init_pin_configs".  Then hda-emu will initialize
the pin-default contents found in hwC0D0/init_pin_configs sysfs file.

You can also pass an external file name to -P option instead of the
sysfs files in the input file.  The file must contain a pair of
register and pin-config value in each line just like in *_pin_configs
sysfs files.  Also, you can pass a pin config directly via -P optoin,
e.g. -P 0x0a=0x12345678.

For providing the user-defined pin configurations, use -U instead of
-P option.  The difference between these two options is that the pin
configuration set via -P option may be overridden by the driver's own
setup while the pin configuration set via -U remains over the driver's
setup.

Similarly, you can give the initial hints strings either from sysfs
file in alsa-info.sh output or an external file via -H option.  Also,
you can pass a hint directrly via -H option, e.g. -H "jack_detect=0".

If you want to debug a certain jack-plug state at the initial time,
pass the pin NID to turn on via -j option.  When nothing is set, all
pins are assumed to be unplugged at the start up.


START WITHOUT CODEC PARSER
--------------------------

When you don't want to start the codec parser procedure, i.e. just
probe the codec and initializes the instance without invoking the
parser, pass -n option.  (This corresponds to probe_only=1 option for
snd-hda-intel module.)

Then you can inspect the pin config, add hints or whatever, then
trigger the codec parser manually later by "fs set reconfig 1" command.


DEBUGGING DRIVER WITH GDB
-------------------------

It's often useful to debug the driver behavior via gdb.  When you pass
-a option to hda-emu, it'll send SIGTRAP when the error is from the
driver; i.e. when printk(KERN_ERR ...) is issued.  Then gdb will trap
it and you can see the code path and invesitage there.

The -a option doesn't affect operations when hda-emu isn't invoked in
gdb or such, as SIGTRAP is ignored as default in hda-emu.


DOWNLOAD
--------

The git tree is found at:
	git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/hda-emu.git

A backup repo is at:
	https://github.com/tiwai/hda-emu


LICENSE
-------

GPL v2.  See COPYING file.