1MORE NOTES ON HD-AUDIO DRIVER
2=============================
3					Takashi Iwai <tiwai@suse.de>
4
5
6GENERAL
7-------
8
9HD-audio is the new standard on-board audio component on modern PCs
10after AC97.  Although Linux has been supporting HD-audio since long
11time ago, there are often problems with new machines.  A part of the
12problem is broken BIOS, and the rest is the driver implementation.
13This document explains the brief trouble-shooting and debugging
14methods for the	HD-audio hardware.
15
16The HD-audio component consists of two parts: the controller chip and 
17the codec chips on the HD-audio bus.  Linux provides a single driver
18for all controllers, snd-hda-intel.  Although the driver name contains
19a word of a well-known hardware vendor, it's not specific to it but for
20all controller chips by other companies.  Since the HD-audio
21controllers are supposed to be compatible, the single snd-hda-driver
22should work in most cases.  But, not surprisingly, there are known
23bugs and issues specific to each controller type.  The snd-hda-intel
24driver has a bunch of workarounds for these as described below.
25
26A controller may have multiple codecs.  Usually you have one audio
27codec and optionally one modem codec.  In theory, there might be
28multiple audio codecs, e.g. for analog and digital outputs, and the
29driver might not work properly because of conflict of mixer elements.
30This should be fixed in future if such hardware really exists.
31
32The snd-hda-intel driver has several different codec parsers depending
33on the codec.  It has a generic parser as a fallback, but this
34functionality is fairly limited until now.  Instead of the generic
35parser, usually the codec-specific parser (coded in patch_*.c) is used
36for the codec-specific implementations.  The details about the
37codec-specific problems are explained in the later sections.
38
39If you are interested in the deep debugging of HD-audio, read the
40HD-audio specification at first.  The specification is found on
41Intel's web page, for example:
42
43- http://www.intel.com/standards/hdaudio/
44
45
46HD-AUDIO CONTROLLER
47-------------------
48
49DMA-Position Problem
50~~~~~~~~~~~~~~~~~~~~
51The most common problem of the controller is the inaccurate DMA
52pointer reporting.  The DMA pointer for playback and capture can be
53read in two ways, either via a LPIB register or via a position-buffer
54map.  As default the driver tries to read from the io-mapped
55position-buffer, and falls back to LPIB if the position-buffer appears
56dead.  However, this detection isn't perfect on some devices.  In such
57a case, you can change the default method via `position_fix` option.
58
59`position_fix=1` means to use LPIB method explicitly.
60`position_fix=2` means to use the position-buffer.
61`position_fix=3` means to use a combination of both methods, needed
62for some VIA controllers.  The capture stream position is corrected
63by comparing both LPIB and position-buffer values.
64`position_fix=4` is another combination available for all controllers,
65and uses LPIB for the playback and the position-buffer for the capture
66streams.
670 is the default value for all other
68controllers, the automatic check and fallback to LPIB as described in
69the above.  If you get a problem of repeated sounds, this option might
70help.
71
72In addition to that, every controller is known to be broken regarding
73the wake-up timing.  It wakes up a few samples before actually
74processing the data on the buffer.  This caused a lot of problems, for
75example, with ALSA dmix or JACK.  Since 2.6.27 kernel, the driver puts
76an artificial delay to the wake up timing.  This delay is controlled
77via `bdl_pos_adj` option. 
78
79When `bdl_pos_adj` is a negative value (as default), it's assigned to
80an appropriate value depending on the controller chip.  For Intel
81chips, it'd be 1 while it'd be 32 for others.  Usually this works.
82Only in case it doesn't work and you get warning messages, you should
83change this parameter to other values.
84
85
86Codec-Probing Problem
87~~~~~~~~~~~~~~~~~~~~~
88A less often but a more severe problem is the codec probing.  When
89BIOS reports the available codec slots wrongly, the driver gets
90confused and tries to access the non-existing codec slot.  This often
91results in the total screw-up, and destructs the further communication
92with the codec chips.  The symptom appears usually as error messages
93like:
94------------------------------------------------------------------------
95  hda_intel: azx_get_response timeout, switching to polling mode:
96        last cmd=0x12345678
97  hda_intel: azx_get_response timeout, switching to single_cmd mode:
98        last cmd=0x12345678
99------------------------------------------------------------------------
100
101The first line is a warning, and this is usually relatively harmless.
102It means that the codec response isn't notified via an IRQ.  The
103driver uses explicit polling method to read the response.  It gives
104very slight CPU overhead, but you'd unlikely notice it.
105
106The second line is, however, a fatal error.  If this happens, usually
107it means that something is really wrong.  Most likely you are
108accessing a non-existing codec slot.
109
110Thus, if the second error message appears, try to narrow the probed
111codec slots via `probe_mask` option.  It's a bitmask, and each bit
112corresponds to the codec slot.  For example, to probe only the first
113slot, pass `probe_mask=1`.  For the first and the third slots, pass
114`probe_mask=5` (where 5 = 1 | 4), and so on.
115
116Since 2.6.29 kernel, the driver has a more robust probing method, so
117this error might happen rarely, though.
118
119On a machine with a broken BIOS, sometimes you need to force the
120driver to probe the codec slots the hardware doesn't report for use.
121In such a case, turn the bit 8 (0x100) of `probe_mask` option on.
122Then the rest 8 bits are passed as the codec slots to probe
123unconditionally.  For example, `probe_mask=0x103` will force to probe
124the codec slots 0 and 1 no matter what the hardware reports.
125
126
127Interrupt Handling
128~~~~~~~~~~~~~~~~~~
129HD-audio driver uses MSI as default (if available) since 2.6.33
130kernel as MSI works better on some machines, and in general, it's
131better for performance.  However, Nvidia controllers showed bad
132regressions with MSI (especially in a combination with AMD chipset),
133thus we disabled MSI for them.
134
135There seem also still other devices that don't work with MSI.  If you
136see a regression wrt the sound quality (stuttering, etc) or a lock-up
137in the recent kernel, try to pass `enable_msi=0` option to disable
138MSI.  If it works, you can add the known bad device to the blacklist
139defined in hda_intel.c.  In such a case, please report and give the
140patch back to the upstream developer. 
141
142
143HD-AUDIO CODEC
144--------------
145
146Model Option
147~~~~~~~~~~~~
148The most common problem regarding the HD-audio driver is the
149unsupported codec features or the mismatched device configuration.
150Most of codec-specific code has several preset models, either to
151override the BIOS setup or to provide more comprehensive features.
152
153The driver checks PCI SSID and looks through the static configuration
154table until any matching entry is found.  If you have a new machine,
155you may see a message like below:
156------------------------------------------------------------------------
157    hda_codec: ALC880: BIOS auto-probing.
158------------------------------------------------------------------------
159Meanwhile, in the earlier versions, you would see a message like:
160------------------------------------------------------------------------
161    hda_codec: Unknown model for ALC880, trying auto-probe from BIOS...
162------------------------------------------------------------------------
163Even if you see such a message, DON'T PANIC.  Take a deep breath and
164keep your towel.  First of all, it's an informational message, no
165warning, no error.  This means that the PCI SSID of your device isn't
166listed in the known preset model (white-)list.  But, this doesn't mean
167that the driver is broken.  Many codec-drivers provide the automatic
168configuration mechanism based on the BIOS setup.
169
170The HD-audio codec has usually "pin" widgets, and BIOS sets the default
171configuration of each pin, which indicates the location, the
172connection type, the jack color, etc.  The HD-audio driver can guess
173the right connection judging from these default configuration values.
174However -- some codec-support codes, such as patch_analog.c, don't
175support the automatic probing (yet as of 2.6.28).  And, BIOS is often,
176yes, pretty often broken.  It sets up wrong values and screws up the
177driver.
178
179The preset model (or recently called as "fix-up") is provided
180basically to overcome such a situation.  When the matching preset
181model is found in the white-list, the driver assumes the static
182configuration of that preset with the correct pin setup, etc.
183Thus, if you have a newer machine with a slightly different PCI SSID
184(or codec SSID) from the existing one, you may have a good chance to
185re-use the same model.  You can pass the `model` option to specify the
186preset model instead of PCI (and codec-) SSID look-up.
187
188What `model` option values are available depends on the codec chip.
189Check your codec chip from the codec proc file (see "Codec Proc-File"
190section below).  It will show the vendor/product name of your codec
191chip.  Then, see Documentation/sound/alsa/HD-Audio-Models.txt file,
192the section of HD-audio driver.  You can find a list of codecs
193and `model` options belonging to each codec.  For example, for Realtek
194ALC262 codec chip, pass `model=ultra` for devices that are compatible
195with Samsung Q1 Ultra.
196
197Thus, the first thing you can do for any brand-new, unsupported and
198non-working HD-audio hardware is to check HD-audio codec and several
199different `model` option values.  If you have any luck, some of them
200might suit with your device well.
201
202There are a few special model option values:
203- when 'nofixup' is passed, the device-specific fixups in the codec
204  parser are skipped.
205- when `generic` is passed, the codec-specific parser is skipped and
206  only the generic parser is used.
207
208
209Speaker and Headphone Output
210~~~~~~~~~~~~~~~~~~~~~~~~~~~~
211One of the most frequent (and obvious) bugs with HD-audio is the
212silent output from either or both of a built-in speaker and a
213headphone jack.  In general, you should try a headphone output at
214first.  A speaker output often requires more additional controls like
215the external amplifier bits.  Thus a headphone output has a slightly
216better chance.
217
218Before making a bug report, double-check whether the mixer is set up
219correctly.  The recent version of snd-hda-intel driver provides mostly
220"Master" volume control as well as "Front" volume (where Front
221indicates the front-channels).  In addition, there can be individual
222"Headphone" and "Speaker" controls.
223
224Ditto for the speaker output.  There can be "External Amplifier"
225switch on some codecs.  Turn on this if present.
226
227Another related problem is the automatic mute of speaker output by
228headphone plugging.  This feature is implemented in most cases, but
229not on every preset model or codec-support code.
230
231In anyway, try a different model option if you have such a problem.
232Some other models may match better and give you more matching
233functionality.  If none of the available models works, send a bug
234report.  See the bug report section for details.
235
236If you are masochistic enough to debug the driver problem, note the
237following:
238
239- The speaker (and the headphone, too) output often requires the
240  external amplifier.  This can be set usually via EAPD verb or a
241  certain GPIO.  If the codec pin supports EAPD, you have a better
242  chance via SET_EAPD_BTL verb (0x70c).  On others, GPIO pin (mostly
243  it's either GPIO0 or GPIO1) may turn on/off EAPD.
244- Some Realtek codecs require special vendor-specific coefficients to
245  turn on the amplifier.  See patch_realtek.c.
246- IDT codecs may have extra power-enable/disable controls on each
247  analog pin.  See patch_sigmatel.c.
248- Very rare but some devices don't accept the pin-detection verb until
249  triggered.  Issuing GET_PIN_SENSE verb (0xf09) may result in the
250  codec-communication stall.  Some examples are found in
251  patch_realtek.c.
252
253
254Capture Problems
255~~~~~~~~~~~~~~~~
256The capture problems are often because of missing setups of mixers.
257Thus, before submitting a bug report, make sure that you set up the
258mixer correctly.  For example, both "Capture Volume" and "Capture
259Switch" have to be set properly in addition to the right "Capture
260Source" or "Input Source" selection.  Some devices have "Mic Boost"
261volume or switch.
262
263When the PCM device is opened via "default" PCM (without pulse-audio
264plugin), you'll likely have "Digital Capture Volume" control as well.
265This is provided for the extra gain/attenuation of the signal in
266software, especially for the inputs without the hardware volume
267control such as digital microphones.  Unless really needed, this
268should be set to exactly 50%, corresponding to 0dB -- neither extra
269gain nor attenuation.  When you use "hw" PCM, i.e., a raw access PCM,
270this control will have no influence, though.
271
272It's known that some codecs / devices have fairly bad analog circuits,
273and the recorded sound contains a certain DC-offset.  This is no bug
274of the driver.
275
276Most of modern laptops have no analog CD-input connection.  Thus, the
277recording from CD input won't work in many cases although the driver
278provides it as the capture source.  Use CDDA instead.
279
280The automatic switching of the built-in and external mic per plugging
281is implemented on some codec models but not on every model.  Partly
282because of my laziness but mostly lack of testers.  Feel free to
283submit the improvement patch to the author.
284
285
286Direct Debugging
287~~~~~~~~~~~~~~~~
288If no model option gives you a better result, and you are a tough guy
289to fight against evil, try debugging via hitting the raw HD-audio
290codec verbs to the device.  Some tools are available: hda-emu and
291hda-analyzer.  The detailed description is found in the sections
292below.  You'd need to enable hwdep for using these tools.  See "Kernel
293Configuration" section.
294
295
296OTHER ISSUES
297------------
298
299Kernel Configuration
300~~~~~~~~~~~~~~~~~~~~
301In general, I recommend you to enable the sound debug option,
302`CONFIG_SND_DEBUG=y`, no matter whether you are debugging or not.
303This enables snd_printd() macro and others, and you'll get additional
304kernel messages at probing.
305
306In addition, you can enable `CONFIG_SND_DEBUG_VERBOSE=y`.  But this
307will give you far more messages.  Thus turn this on only when you are
308sure to want it.
309
310Don't forget to turn on the appropriate `CONFIG_SND_HDA_CODEC_*`
311options.  Note that each of them corresponds to the codec chip, not
312the controller chip.  Thus, even if lspci shows the Nvidia controller,
313you may need to choose the option for other vendors.  If you are
314unsure, just select all yes.
315
316`CONFIG_SND_HDA_HWDEP` is a useful option for debugging the driver.
317When this is enabled, the driver creates hardware-dependent devices
318(one per each codec), and you have a raw access to the device via
319these device files.  For example, `hwC0D2` will be created for the
320codec slot #2 of the first card (#0).  For debug-tools such as
321hda-verb and hda-analyzer, the hwdep device has to be enabled.
322Thus, it'd be better to turn this on always.
323
324`CONFIG_SND_HDA_RECONFIG` is a new option, and this depends on the
325hwdep option above.  When enabled, you'll have some sysfs files under
326the corresponding hwdep directory.  See "HD-audio reconfiguration"
327section below.
328
329`CONFIG_SND_HDA_POWER_SAVE` option enables the power-saving feature.
330See "Power-saving" section below.
331
332
333Codec Proc-File
334~~~~~~~~~~~~~~~
335The codec proc-file is a treasure-chest for debugging HD-audio.
336It shows most of useful information of each codec widget.
337
338The proc file is located in /proc/asound/card*/codec#*, one file per
339each codec slot.  You can know the codec vendor, product id and
340names, the type of each widget, capabilities and so on.
341This file, however, doesn't show the jack sensing state, so far.  This
342is because the jack-sensing might be depending on the trigger state.
343
344This file will be picked up by the debug tools, and also it can be fed
345to the emulator as the primary codec information.  See the debug tools
346section below.
347
348This proc file can be also used to check whether the generic parser is
349used.  When the generic parser is used, the vendor/product ID name
350will appear as "Realtek ID 0262", instead of "Realtek ALC262".
351
352
353HD-Audio Reconfiguration
354~~~~~~~~~~~~~~~~~~~~~~~~
355This is an experimental feature to allow you re-configure the HD-audio
356codec dynamically without reloading the driver.  The following sysfs
357files are available under each codec-hwdep device directory (e.g. 
358/sys/class/sound/hwC0D0):
359
360vendor_id::
361  Shows the 32bit codec vendor-id hex number.  You can change the
362  vendor-id value by writing to this file.
363subsystem_id::
364  Shows the 32bit codec subsystem-id hex number.  You can change the
365  subsystem-id value by writing to this file.
366revision_id::
367  Shows the 32bit codec revision-id hex number.  You can change the
368  revision-id value by writing to this file.
369afg::
370  Shows the AFG ID.  This is read-only.
371mfg::
372  Shows the MFG ID.  This is read-only.
373name::
374  Shows the codec name string.  Can be changed by writing to this
375  file.
376modelname::
377  Shows the currently set `model` option.  Can be changed by writing
378  to this file.
379init_verbs::
380  The extra verbs to execute at initialization.  You can add a verb by
381  writing to this file.  Pass three numbers: nid, verb and parameter
382  (separated with a space).
383hints::
384  Shows / stores hint strings for codec parsers for any use.
385  Its format is `key = value`.  For example, passing `jack_detect = no`
386  will disable the jack detection of the machine completely.
387init_pin_configs::
388  Shows the initial pin default config values set by BIOS.
389driver_pin_configs::
390  Shows the pin default values set by the codec parser explicitly.
391  This doesn't show all pin values but only the changed values by
392  the parser.  That is, if the parser doesn't change the pin default
393  config values by itself, this will contain nothing.
394user_pin_configs::
395  Shows the pin default config values to override the BIOS setup.
396  Writing this (with two numbers, NID and value) appends the new
397  value.  The given will be used instead of the initial BIOS value at
398  the next reconfiguration time.  Note that this config will override
399  even the driver pin configs, too.
400reconfig::
401  Triggers the codec re-configuration.  When any value is written to
402  this file, the driver re-initialize and parses the codec tree
403  again.  All the changes done by the sysfs entries above are taken
404  into account.
405clear::
406  Resets the codec, removes the mixer elements and PCM stuff of the
407  specified codec, and clear all init verbs and hints.
408
409For example, when you want to change the pin default configuration
410value of the pin widget 0x14 to 0x9993013f, and let the driver
411re-configure based on that state, run like below:
412------------------------------------------------------------------------
413  # echo 0x14 0x9993013f > /sys/class/sound/hwC0D0/user_pin_configs
414  # echo 1 > /sys/class/sound/hwC0D0/reconfig  
415------------------------------------------------------------------------
416
417
418Hint Strings
419~~~~~~~~~~~~
420The codec parser have several switches and adjustment knobs for
421matching better with the actual codec or device behavior.  Many of
422them can be adjusted dynamically via "hints" strings as mentioned in
423the section above.  For example, by passing `jack_detect = no` string
424via sysfs or a patch file, you can disable the jack detection, thus
425the codec parser will skip the features like auto-mute or mic
426auto-switch.  As a boolean value, either `yes`, `no`, `true`, `false`,
427`1` or `0` can be passed.
428
429The generic parser supports the following hints:
430
431- jack_detect (bool): specify whether the jack detection is available
432  at all on this machine; default true
433- inv_jack_detect (bool): indicates that the jack detection logic is
434  inverted
435- trigger_sense (bool): indicates that the jack detection needs the
436  explicit call of AC_VERB_SET_PIN_SENSE verb
437- inv_eapd (bool): indicates that the EAPD is implemented in the
438  inverted logic
439- pcm_format_first (bool): sets the PCM format before the stream tag
440  and channel ID
441- sticky_stream (bool): keep the PCM format, stream tag and ID as long
442  as possible; default true
443- spdif_status_reset (bool): reset the SPDIF status bits at each time
444  the SPDIF stream is set up
445-  pin_amp_workaround (bool): the output pin may have multiple amp
446  values
447- single_adc_amp (bool): ADCs can have only single input amps
448- auto_mute (bool): enable/disable the headphone auto-mute feature;
449  default true
450- auto_mic (bool): enable/disable the mic auto-switch feature; default
451  true
452- line_in_auto_switch (bool): enable/disable the line-in auto-switch
453  feature; default false
454- need_dac_fix (bool): limits the DACs depending on the channel count
455- primary_hp (bool): probe headphone jacks as the primary outputs;
456  default true
457- multi_io (bool): try probing multi-I/O config (e.g. shared
458  line-in/surround, mic/clfe jacks)
459- multi_cap_vol (bool): provide multiple capture volumes
460- inv_dmic_split (bool): provide split internal mic volume/switch for
461  phase-inverted digital mics
462- indep_hp (bool): provide the independent headphone PCM stream and
463  the corresponding mixer control, if available
464- add_stereo_mix_input (bool): add the stereo mix (analog-loopback
465  mix) to the input mux if available
466- add_jack_modes (bool): add "xxx Jack Mode" enum controls to each
467  I/O jack for allowing to change the headphone amp and mic bias VREF
468  capabilities
469- power_save_node (bool): advanced power management for each widget,
470  controlling the power sate (D0/D3) of each widget node depending on
471  the actual pin and stream states
472- power_down_unused (bool): power down the unused widgets, a subset of
473  power_save_node, and will be dropped in future
474- add_hp_mic (bool): add the headphone to capture source if possible
475- hp_mic_detect (bool): enable/disable the hp/mic shared input for a
476  single built-in mic case; default true
477- mixer_nid (int): specifies the widget NID of the analog-loopback
478  mixer
479
480
481Early Patching
482~~~~~~~~~~~~~~
483When CONFIG_SND_HDA_PATCH_LOADER=y is set, you can pass a "patch" as a
484firmware file for modifying the HD-audio setup before initializing the
485codec.  This can work basically like the reconfiguration via sysfs in
486the above, but it does it before the first codec configuration.
487
488A patch file is a plain text file which looks like below:
489
490------------------------------------------------------------------------
491  [codec]
492  0x12345678 0xabcd1234 2
493
494  [model]
495  auto
496
497  [pincfg]
498  0x12 0x411111f0
499
500  [verb]
501  0x20 0x500 0x03
502  0x20 0x400 0xff
503
504  [hint]
505  jack_detect = no
506------------------------------------------------------------------------
507
508The file needs to have a line `[codec]`.  The next line should contain
509three numbers indicating the codec vendor-id (0x12345678 in the
510example), the codec subsystem-id (0xabcd1234) and the address (2) of
511the codec.  The rest patch entries are applied to this specified codec
512until another codec entry is given.  Passing 0 or a negative number to
513the first or the second value will make the check of the corresponding
514field be skipped.  It'll be useful for really broken devices that don't
515initialize SSID properly.
516
517The `[model]` line allows to change the model name of the each codec.
518In the example above, it will be changed to model=auto.
519Note that this overrides the module option.
520
521After the `[pincfg]` line, the contents are parsed as the initial
522default pin-configurations just like `user_pin_configs` sysfs above.
523The values can be shown in user_pin_configs sysfs file, too.
524
525Similarly, the lines after `[verb]` are parsed as `init_verbs`
526sysfs entries, and the lines after `[hint]` are parsed as `hints`
527sysfs entries, respectively.
528
529Another example to override the codec vendor id from 0x12345678 to
5300xdeadbeef is like below:
531------------------------------------------------------------------------
532  [codec]
533  0x12345678 0xabcd1234 2
534
535  [vendor_id]
536  0xdeadbeef
537------------------------------------------------------------------------
538
539In the similar way, you can override the codec subsystem_id via
540`[subsystem_id]`, the revision id via `[revision_id]` line.
541Also, the codec chip name can be rewritten via `[chip_name]` line.
542------------------------------------------------------------------------
543  [codec]
544  0x12345678 0xabcd1234 2
545
546  [subsystem_id]
547  0xffff1111
548
549  [revision_id]
550  0x10
551
552  [chip_name]
553  My-own NEWS-0002
554------------------------------------------------------------------------
555
556The hd-audio driver reads the file via request_firmware().  Thus,
557a patch file has to be located on the appropriate firmware path,
558typically, /lib/firmware.  For example, when you pass the option
559`patch=hda-init.fw`, the file /lib/firmware/hda-init.fw must be
560present.
561
562The patch module option is specific to each card instance, and you
563need to give one file name for each instance, separated by commas.
564For example, if you have two cards, one for an on-board analog and one 
565for an HDMI video board, you may pass patch option like below:
566------------------------------------------------------------------------
567    options snd-hda-intel patch=on-board-patch,hdmi-patch
568------------------------------------------------------------------------
569
570
571Power-Saving
572~~~~~~~~~~~~
573The power-saving is a kind of auto-suspend of the device.  When the
574device is inactive for a certain time, the device is automatically
575turned off to save the power.  The time to go down is specified via
576`power_save` module option, and this option can be changed dynamically
577via sysfs.
578
579The power-saving won't work when the analog loopback is enabled on
580some codecs.  Make sure that you mute all unneeded signal routes when
581you want the power-saving.
582
583The power-saving feature might cause audible click noises at each
584power-down/up depending on the device.  Some of them might be
585solvable, but some are hard, I'm afraid.  Some distros such as
586openSUSE enables the power-saving feature automatically when the power
587cable is unplugged.  Thus, if you hear noises, suspect first the
588power-saving.  See /sys/module/snd_hda_intel/parameters/power_save to
589check the current value.  If it's non-zero, the feature is turned on.
590
591The recent kernel supports the runtime PM for the HD-audio controller
592chip, too.  It means that the HD-audio controller is also powered up /
593down dynamically.  The feature is enabled only for certain controller
594chips like Intel LynxPoint.  You can enable/disable this feature
595forcibly by setting `power_save_controller` option, which is also
596available at /sys/module/snd_hda_intel/parameters directory.
597
598
599Tracepoints
600~~~~~~~~~~~
601The hd-audio driver gives a few basic tracepoints.
602`hda:hda_send_cmd` traces each CORB write while `hda:hda_get_response`
603traces the response from RIRB (only when read from the codec driver).
604`hda:hda_bus_reset` traces the bus-reset due to fatal error, etc,
605`hda:hda_unsol_event` traces the unsolicited events, and
606`hda:hda_power_down` and `hda:hda_power_up` trace the power down/up
607via power-saving behavior.
608
609Enabling all tracepoints can be done like
610------------------------------------------------------------------------
611  # echo 1 > /sys/kernel/debug/tracing/events/hda/enable
612------------------------------------------------------------------------
613then after some commands, you can traces from
614/sys/kernel/debug/tracing/trace file.  For example, when you want to
615trace what codec command is sent, enable the tracepoint like:
616------------------------------------------------------------------------
617  # cat /sys/kernel/debug/tracing/trace
618  # tracer: nop
619  #
620  #       TASK-PID    CPU#    TIMESTAMP  FUNCTION
621  #          | |       |          |         |
622         <...>-7807  [002] 105147.774889: hda_send_cmd: [0:0] val=e3a019
623         <...>-7807  [002] 105147.774893: hda_send_cmd: [0:0] val=e39019
624         <...>-7807  [002] 105147.999542: hda_send_cmd: [0:0] val=e3a01a
625         <...>-7807  [002] 105147.999543: hda_send_cmd: [0:0] val=e3901a
626         <...>-26764 [001] 349222.837143: hda_send_cmd: [0:0] val=e3a019
627         <...>-26764 [001] 349222.837148: hda_send_cmd: [0:0] val=e39019
628         <...>-26764 [001] 349223.058539: hda_send_cmd: [0:0] val=e3a01a
629         <...>-26764 [001] 349223.058541: hda_send_cmd: [0:0] val=e3901a
630------------------------------------------------------------------------
631Here `[0:0]` indicates the card number and the codec address, and
632`val` shows the value sent to the codec, respectively.  The value is
633a packed value, and you can decode it via hda-decode-verb program
634included in hda-emu package below.  For example, the value e3a019 is
635to set the left output-amp value to 25.
636------------------------------------------------------------------------
637  % hda-decode-verb 0xe3a019
638  raw value = 0x00e3a019
639  cid = 0, nid = 0x0e, verb = 0x3a0, parm = 0x19
640  raw value: verb = 0x3a0, parm = 0x19
641  verbname = set_amp_gain_mute
642  amp raw val = 0xa019
643  output, left, idx=0, mute=0, val=25
644------------------------------------------------------------------------
645
646
647Development Tree
648~~~~~~~~~~~~~~~~
649The latest development codes for HD-audio are found on sound git tree:
650
651- git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git
652
653The master branch or for-next branches can be used as the main
654development branches in general while the development for the current
655and next kernels are found in for-linus and for-next branches,
656respectively.
657
658If you are using the latest Linus tree, it'd be better to pull the
659above GIT tree onto it.  If you are using the older kernels, an easy
660way to try the latest ALSA code is to build from the snapshot
661tarball.  There are daily tarballs and the latest snapshot tarball.
662All can be built just like normal alsa-driver release packages, that
663is, installed via the usual spells: configure, make and make
664install(-modules).  See INSTALL in the package.  The snapshot tarballs
665are found at:
666
667- ftp://ftp.suse.com/pub/people/tiwai/snapshot/
668
669
670Sending a Bug Report
671~~~~~~~~~~~~~~~~~~~~
672If any model or module options don't work for your device, it's time
673to send a bug report to the developers.  Give the following in your
674bug report:
675
676- Hardware vendor, product and model names
677- Kernel version (and ALSA-driver version if you built externally)
678- `alsa-info.sh` output; run with `--no-upload` option.  See the
679  section below about alsa-info
680
681If it's a regression, at best, send alsa-info outputs of both working
682and non-working kernels.  This is really helpful because we can
683compare the codec registers directly.
684
685Send a bug report either the followings:
686
687kernel-bugzilla::
688  https://bugzilla.kernel.org/
689alsa-devel ML::
690  alsa-devel@alsa-project.org
691
692
693DEBUG TOOLS
694-----------
695
696This section describes some tools available for debugging HD-audio
697problems.
698
699alsa-info
700~~~~~~~~~
701The script `alsa-info.sh` is a very useful tool to gather the audio
702device information.  You can fetch the latest version from:
703
704- http://www.alsa-project.org/alsa-info.sh
705
706Run this script as root, and it will gather the important information
707such as the module lists, module parameters, proc file contents
708including the codec proc files, mixer outputs and the control
709elements.  As default, it will store the information onto a web server
710on alsa-project.org.  But, if you send a bug report, it'd be better to
711run with `--no-upload` option, and attach the generated file.
712
713There are some other useful options.  See `--help` option output for
714details.
715
716When a probe error occurs or when the driver obviously assigns a
717mismatched model, it'd be helpful to load the driver with
718`probe_only=1` option (at best after the cold reboot) and run
719alsa-info at this state.  With this option, the driver won't configure
720the mixer and PCM but just tries to probe the codec slot.  After
721probing, the proc file is available, so you can get the raw codec
722information before modified by the driver.  Of course, the driver
723isn't usable with `probe_only=1`.  But you can continue the
724configuration via hwdep sysfs file if hda-reconfig option is enabled.
725Using `probe_only` mask 2 skips the reset of HDA codecs (use
726`probe_only=3` as module option). The hwdep interface can be used
727to determine the BIOS codec initialization.
728
729
730hda-verb
731~~~~~~~~
732hda-verb is a tiny program that allows you to access the HD-audio
733codec directly.  You can execute a raw HD-audio codec verb with this.
734This program accesses the hwdep device, thus you need to enable the
735kernel config `CONFIG_SND_HDA_HWDEP=y` beforehand.
736
737The hda-verb program takes four arguments: the hwdep device file, the
738widget NID, the verb and the parameter.  When you access to the codec
739on the slot 2 of the card 0, pass /dev/snd/hwC0D2 to the first
740argument, typically.  (However, the real path name depends on the
741system.)
742
743The second parameter is the widget number-id to access.  The third
744parameter can be either a hex/digit number or a string corresponding
745to a verb.  Similarly, the last parameter is the value to write, or
746can be a string for the parameter type.
747
748------------------------------------------------------------------------
749  % hda-verb /dev/snd/hwC0D0 0x12 0x701 2
750  nid = 0x12, verb = 0x701, param = 0x2
751  value = 0x0
752
753  % hda-verb /dev/snd/hwC0D0 0x0 PARAMETERS VENDOR_ID
754  nid = 0x0, verb = 0xf00, param = 0x0
755  value = 0x10ec0262
756
757  % hda-verb /dev/snd/hwC0D0 2 set_a 0xb080
758  nid = 0x2, verb = 0x300, param = 0xb080
759  value = 0x0
760------------------------------------------------------------------------
761
762Although you can issue any verbs with this program, the driver state
763won't be always updated.  For example, the volume values are usually
764cached in the driver, and thus changing the widget amp value directly
765via hda-verb won't change the mixer value.
766
767The hda-verb program is included now in alsa-tools:
768
769- git://git.alsa-project.org/alsa-tools.git
770
771Also, the old stand-alone package is found in the ftp directory:
772
773- ftp://ftp.suse.com/pub/people/tiwai/misc/
774
775Also a git repository is available:
776
777- git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/hda-verb.git
778
779See README file in the tarball for more details about hda-verb
780program.
781
782
783hda-analyzer
784~~~~~~~~~~~~
785hda-analyzer provides a graphical interface to access the raw HD-audio
786control, based on pyGTK2 binding.  It's a more powerful version of
787hda-verb.  The program gives you an easy-to-use GUI stuff for showing
788the widget information and adjusting the amp values, as well as the
789proc-compatible output.
790
791The hda-analyzer:
792
793- http://git.alsa-project.org/?p=alsa.git;a=tree;f=hda-analyzer
794
795is a part of alsa.git repository in alsa-project.org:
796
797- git://git.alsa-project.org/alsa.git
798
799Codecgraph
800~~~~~~~~~~
801Codecgraph is a utility program to generate a graph and visualizes the
802codec-node connection of a codec chip.  It's especially useful when
803you analyze or debug a codec without a proper datasheet.  The program
804parses the given codec proc file and converts to SVG via graphiz
805program.
806
807The tarball and GIT trees are found in the web page at:
808
809- http://helllabs.org/codecgraph/
810
811
812hda-emu
813~~~~~~~
814hda-emu is an HD-audio emulator.  The main purpose of this program is
815to debug an HD-audio codec without the real hardware.  Thus, it
816doesn't emulate the behavior with the real audio I/O, but it just
817dumps the codec register changes and the ALSA-driver internal changes
818at probing and operating the HD-audio driver.
819
820The program requires a codec proc-file to simulate.  Get a proc file
821for the target codec beforehand, or pick up an example codec from the
822codec proc collections in the tarball.  Then, run the program with the
823proc file, and the hda-emu program will start parsing the codec file
824and simulates the HD-audio driver:
825
826------------------------------------------------------------------------
827  % hda-emu codecs/stac9200-dell-d820-laptop
828  # Parsing..
829  hda_codec: Unknown model for STAC9200, using BIOS defaults
830  hda_codec: pin nid 08 bios pin config 40c003fa
831  ....
832------------------------------------------------------------------------
833
834The program gives you only a very dumb command-line interface.  You
835can get a proc-file dump at the current state, get a list of control
836(mixer) elements, set/get the control element value, simulate the PCM
837operation, the jack plugging simulation, etc.
838
839The package is found in:
840
841- ftp://ftp.suse.com/pub/people/tiwai/misc/
842
843A git repository is available:
844
845- git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/hda-emu.git
846
847See README file in the tarball for more details about hda-emu
848program.
849
850
851hda-jack-retask
852~~~~~~~~~~~~~~~
853hda-jack-retask is a user-friendly GUI program to manipulate the
854HD-audio pin control for jack retasking.  If you have a problem about
855the jack assignment, try this program and check whether you can get
856useful results.  Once when you figure out the proper pin assignment,
857it can be fixed either in the driver code statically or via passing a
858firmware patch file (see "Early Patching" section).
859
860The program is included in alsa-tools now:
861
862- git://git.alsa-project.org/alsa-tools.git
863
864