Based on kernel version 2.6.34. Page generated on 2010-05-31 16:03 EST.
1 MORE NOTES ON HD-AUDIO DRIVER 2 ============================= 3 Takashi Iwai <tiwai[AT]suse[DOT]de> 4 5 6 GENERAL 7 ------- 8 9 HD-audio is the new standard on-board audio component on modern PCs 10 after AC97. Although Linux has been supporting HD-audio since long 11 time ago, there are often problems with new machines. A part of the 12 problem is broken BIOS, and the rest is the driver implementation. 13 This document explains the brief trouble-shooting and debugging 14 methods for the HD-audio hardware. 15 16 The HD-audio component consists of two parts: the controller chip and 17 the codec chips on the HD-audio bus. Linux provides a single driver 18 for all controllers, snd-hda-intel. Although the driver name contains 19 a word of a well-known hardware vendor, it's not specific to it but for 20 all controller chips by other companies. Since the HD-audio 21 controllers are supposed to be compatible, the single snd-hda-driver 22 should work in most cases. But, not surprisingly, there are known 23 bugs and issues specific to each controller type. The snd-hda-intel 24 driver has a bunch of workarounds for these as described below. 25 26 A controller may have multiple codecs. Usually you have one audio 27 codec and optionally one modem codec. In theory, there might be 28 multiple audio codecs, e.g. for analog and digital outputs, and the 29 driver might not work properly because of conflict of mixer elements. 30 This should be fixed in future if such hardware really exists. 31 32 The snd-hda-intel driver has several different codec parsers depending 33 on the codec. It has a generic parser as a fallback, but this 34 functionality is fairly limited until now. Instead of the generic 35 parser, usually the codec-specific parser (coded in patch_*.c) is used 36 for the codec-specific implementations. The details about the 37 codec-specific problems are explained in the later sections. 38 39 If you are interested in the deep debugging of HD-audio, read the 40 HD-audio specification at first. The specification is found on 41 Intel's web page, for example: 42 43 - http://www.intel.com/standards/hdaudio/ 44 45 46 HD-AUDIO CONTROLLER 47 ------------------- 48 49 DMA-Position Problem 50 ~~~~~~~~~~~~~~~~~~~~ 51 The most common problem of the controller is the inaccurate DMA 52 pointer reporting. The DMA pointer for playback and capture can be 53 read in two ways, either via a LPIB register or via a position-buffer 54 map. As default the driver tries to read from the io-mapped 55 position-buffer, and falls back to LPIB if the position-buffer appears 56 dead. However, this detection isn't perfect on some devices. In such 57 a 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. 0 is the default 61 value, the automatic check and fallback to LPIB as described in the 62 above. If you get a problem of repeated sounds, this option might 63 help. 64 65 In addition to that, every controller is known to be broken regarding 66 the wake-up timing. It wakes up a few samples before actually 67 processing the data on the buffer. This caused a lot of problems, for 68 example, with ALSA dmix or JACK. Since 2.6.27 kernel, the driver puts 69 an artificial delay to the wake up timing. This delay is controlled 70 via `bdl_pos_adj` option. 71 72 When `bdl_pos_adj` is a negative value (as default), it's assigned to 73 an appropriate value depending on the controller chip. For Intel 74 chips, it'd be 1 while it'd be 32 for others. Usually this works. 75 Only in case it doesn't work and you get warning messages, you should 76 change this parameter to other values. 77 78 79 Codec-Probing Problem 80 ~~~~~~~~~~~~~~~~~~~~~ 81 A less often but a more severe problem is the codec probing. When 82 BIOS reports the available codec slots wrongly, the driver gets 83 confused and tries to access the non-existing codec slot. This often 84 results in the total screw-up, and destructs the further communication 85 with the codec chips. The symptom appears usually as error messages 86 like: 87 ------------------------------------------------------------------------ 88 hda_intel: azx_get_response timeout, switching to polling mode: 89 last cmd=0x12345678 90 hda_intel: azx_get_response timeout, switching to single_cmd mode: 91 last cmd=0x12345678 92 ------------------------------------------------------------------------ 93 94 The first line is a warning, and this is usually relatively harmless. 95 It means that the codec response isn't notified via an IRQ. The 96 driver uses explicit polling method to read the response. It gives 97 very slight CPU overhead, but you'd unlikely notice it. 98 99 The second line is, however, a fatal error. If this happens, usually 100 it means that something is really wrong. Most likely you are 101 accessing a non-existing codec slot. 102 103 Thus, if the second error message appears, try to narrow the probed 104 codec slots via `probe_mask` option. It's a bitmask, and each bit 105 corresponds to the codec slot. For example, to probe only the first 106 slot, pass `probe_mask=1`. For the first and the third slots, pass 107 `probe_mask=5` (where 5 = 1 | 4), and so on. 108 109 Since 2.6.29 kernel, the driver has a more robust probing method, so 110 this error might happen rarely, though. 111 112 On a machine with a broken BIOS, sometimes you need to force the 113 driver to probe the codec slots the hardware doesn't report for use. 114 In such a case, turn the bit 8 (0x100) of `probe_mask` option on. 115 Then the rest 8 bits are passed as the codec slots to probe 116 unconditionally. For example, `probe_mask=0x103` will force to probe 117 the codec slots 0 and 1 no matter what the hardware reports. 118 119 120 Interrupt Handling 121 ~~~~~~~~~~~~~~~~~~ 122 HD-audio driver uses MSI as default (if available) since 2.6.33 123 kernel as MSI works better on some machines, and in general, it's 124 better for performance. However, Nvidia controllers showed bad 125 regressions with MSI (especially in a combination with AMD chipset), 126 thus we disabled MSI for them. 127 128 There seem also still other devices that don't work with MSI. If you 129 see a regression wrt the sound quality (stuttering, etc) or a lock-up 130 in the recent kernel, try to pass `enable_msi=0` option to disable 131 MSI. If it works, you can add the known bad device to the blacklist 132 defined in hda_intel.c. In such a case, please report and give the 133 patch back to the upstream developer. 134 135 136 HD-AUDIO CODEC 137 -------------- 138 139 Model Option 140 ~~~~~~~~~~~~ 141 The most common problem regarding the HD-audio driver is the 142 unsupported codec features or the mismatched device configuration. 143 Most of codec-specific code has several preset models, either to 144 override the BIOS setup or to provide more comprehensive features. 145 146 The driver checks PCI SSID and looks through the static configuration 147 table until any matching entry is found. If you have a new machine, 148 you may see a message like below: 149 ------------------------------------------------------------------------ 150 hda_codec: ALC880: BIOS auto-probing. 151 ------------------------------------------------------------------------ 152 Meanwhile, in the earlier versions, you would see a message like: 153 ------------------------------------------------------------------------ 154 hda_codec: Unknown model for ALC880, trying auto-probe from BIOS... 155 ------------------------------------------------------------------------ 156 Even if you see such a message, DON'T PANIC. Take a deep breath and 157 keep your towel. First of all, it's an informational message, no 158 warning, no error. This means that the PCI SSID of your device isn't 159 listed in the known preset model (white-)list. But, this doesn't mean 160 that the driver is broken. Many codec-drivers provide the automatic 161 configuration mechanism based on the BIOS setup. 162 163 The HD-audio codec has usually "pin" widgets, and BIOS sets the default 164 configuration of each pin, which indicates the location, the 165 connection type, the jack color, etc. The HD-audio driver can guess 166 the right connection judging from these default configuration values. 167 However -- some codec-support codes, such as patch_analog.c, don't 168 support the automatic probing (yet as of 2.6.28). And, BIOS is often, 169 yes, pretty often broken. It sets up wrong values and screws up the 170 driver. 171 172 The preset model is provided basically to overcome such a situation. 173 When the matching preset model is found in the white-list, the driver 174 assumes the static configuration of that preset and builds the mixer 175 elements and PCM streams based on the static information. Thus, if 176 you have a newer machine with a slightly different PCI SSID from the 177 existing one, you may have a good chance to re-use the same model. 178 You can pass the `model` option to specify the preset model instead of 179 PCI SSID look-up. 180 181 What `model` option values are available depends on the codec chip. 182 Check your codec chip from the codec proc file (see "Codec Proc-File" 183 section below). It will show the vendor/product name of your codec 184 chip. Then, see Documentation/sound/alsa/HD-Audio-Models.txt file, 185 the section of HD-audio driver. You can find a list of codecs 186 and `model` options belonging to each codec. For example, for Realtek 187 ALC262 codec chip, pass `model=ultra` for devices that are compatible 188 with Samsung Q1 Ultra. 189 190 Thus, the first thing you can do for any brand-new, unsupported and 191 non-working HD-audio hardware is to check HD-audio codec and several 192 different `model` option values. If you have any luck, some of them 193 might suit with your device well. 194 195 Some codecs such as ALC880 have a special model option `model=test`. 196 This configures the driver to provide as many mixer controls as 197 possible for every single pin feature except for the unsolicited 198 events (and maybe some other specials). Adjust each mixer element and 199 try the I/O in the way of trial-and-error until figuring out the whole 200 I/O pin mappings. 201 202 Note that `model=generic` has a special meaning. It means to use the 203 generic parser regardless of the codec. Usually the codec-specific 204 parser is much better than the generic parser (as now). Thus this 205 option is more about the debugging purpose. 206 207 208 Speaker and Headphone Output 209 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 210 One of the most frequent (and obvious) bugs with HD-audio is the 211 silent output from either or both of a built-in speaker and a 212 headphone jack. In general, you should try a headphone output at 213 first. A speaker output often requires more additional controls like 214 the external amplifier bits. Thus a headphone output has a slightly 215 better chance. 216 217 Before making a bug report, double-check whether the mixer is set up 218 correctly. The recent version of snd-hda-intel driver provides mostly 219 "Master" volume control as well as "Front" volume (where Front 220 indicates the front-channels). In addition, there can be individual 221 "Headphone" and "Speaker" controls. 222 223 Ditto for the speaker output. There can be "External Amplifier" 224 switch on some codecs. Turn on this if present. 225 226 Another related problem is the automatic mute of speaker output by 227 headphone plugging. This feature is implemented in most cases, but 228 not on every preset model or codec-support code. 229 230 In anyway, try a different model option if you have such a problem. 231 Some other models may match better and give you more matching 232 functionality. If none of the available models works, send a bug 233 report. See the bug report section for details. 234 235 If you are masochistic enough to debug the driver problem, note the 236 following: 237 238 - The speaker (and the headphone, too) output often requires the 239 external amplifier. This can be set usually via EAPD verb or a 240 certain GPIO. If the codec pin supports EAPD, you have a better 241 chance via SET_EAPD_BTL verb (0x70c). On others, GPIO pin (mostly 242 it's either GPIO0 or GPIO1) may turn on/off EAPD. 243 - Some Realtek codecs require special vendor-specific coefficients to 244 turn on the amplifier. See patch_realtek.c. 245 - IDT codecs may have extra power-enable/disable controls on each 246 analog pin. See patch_sigmatel.c. 247 - Very rare but some devices don't accept the pin-detection verb until 248 triggered. Issuing GET_PIN_SENSE verb (0xf09) may result in the 249 codec-communication stall. Some examples are found in 250 patch_realtek.c. 251 252 253 Capture Problems 254 ~~~~~~~~~~~~~~~~ 255 The capture problems are often because of missing setups of mixers. 256 Thus, before submitting a bug report, make sure that you set up the 257 mixer correctly. For example, both "Capture Volume" and "Capture 258 Switch" have to be set properly in addition to the right "Capture 259 Source" or "Input Source" selection. Some devices have "Mic Boost" 260 volume or switch. 261 262 When the PCM device is opened via "default" PCM (without pulse-audio 263 plugin), you'll likely have "Digital Capture Volume" control as well. 264 This is provided for the extra gain/attenuation of the signal in 265 software, especially for the inputs without the hardware volume 266 control such as digital microphones. Unless really needed, this 267 should be set to exactly 50%, corresponding to 0dB -- neither extra 268 gain nor attenuation. When you use "hw" PCM, i.e., a raw access PCM, 269 this control will have no influence, though. 270 271 It's known that some codecs / devices have fairly bad analog circuits, 272 and the recorded sound contains a certain DC-offset. This is no bug 273 of the driver. 274 275 Most of modern laptops have no analog CD-input connection. Thus, the 276 recording from CD input won't work in many cases although the driver 277 provides it as the capture source. Use CDDA instead. 278 279 The automatic switching of the built-in and external mic per plugging 280 is implemented on some codec models but not on every model. Partly 281 because of my laziness but mostly lack of testers. Feel free to 282 submit the improvement patch to the author. 283 284 285 Direct Debugging 286 ~~~~~~~~~~~~~~~~ 287 If no model option gives you a better result, and you are a tough guy 288 to fight against evil, try debugging via hitting the raw HD-audio 289 codec verbs to the device. Some tools are available: hda-emu and 290 hda-analyzer. The detailed description is found in the sections 291 below. You'd need to enable hwdep for using these tools. See "Kernel 292 Configuration" section. 293 294 295 OTHER ISSUES 296 ------------ 297 298 Kernel Configuration 299 ~~~~~~~~~~~~~~~~~~~~ 300 In general, I recommend you to enable the sound debug option, 301 `CONFIG_SND_DEBUG=y`, no matter whether you are debugging or not. 302 This enables snd_printd() macro and others, and you'll get additional 303 kernel messages at probing. 304 305 In addition, you can enable `CONFIG_SND_DEBUG_VERBOSE=y`. But this 306 will give you far more messages. Thus turn this on only when you are 307 sure to want it. 308 309 Don't forget to turn on the appropriate `CONFIG_SND_HDA_CODEC_*` 310 options. Note that each of them corresponds to the codec chip, not 311 the controller chip. Thus, even if lspci shows the Nvidia controller, 312 you may need to choose the option for other vendors. If you are 313 unsure, just select all yes. 314 315 `CONFIG_SND_HDA_HWDEP` is a useful option for debugging the driver. 316 When this is enabled, the driver creates hardware-dependent devices 317 (one per each codec), and you have a raw access to the device via 318 these device files. For example, `hwC0D2` will be created for the 319 codec slot #2 of the first card (#0). For debug-tools such as 320 hda-verb and hda-analyzer, the hwdep device has to be enabled. 321 Thus, it'd be better to turn this on always. 322 323 `CONFIG_SND_HDA_RECONFIG` is a new option, and this depends on the 324 hwdep option above. When enabled, you'll have some sysfs files under 325 the corresponding hwdep directory. See "HD-audio reconfiguration" 326 section below. 327 328 `CONFIG_SND_HDA_POWER_SAVE` option enables the power-saving feature. 329 See "Power-saving" section below. 330 331 332 Codec Proc-File 333 ~~~~~~~~~~~~~~~ 334 The codec proc-file is a treasure-chest for debugging HD-audio. 335 It shows most of useful information of each codec widget. 336 337 The proc file is located in /proc/asound/card*/codec#*, one file per 338 each codec slot. You can know the codec vendor, product id and 339 names, the type of each widget, capabilities and so on. 340 This file, however, doesn't show the jack sensing state, so far. This 341 is because the jack-sensing might be depending on the trigger state. 342 343 This file will be picked up by the debug tools, and also it can be fed 344 to the emulator as the primary codec information. See the debug tools 345 section below. 346 347 This proc file can be also used to check whether the generic parser is 348 used. When the generic parser is used, the vendor/product ID name 349 will appear as "Realtek ID 0262", instead of "Realtek ALC262". 350 351 352 HD-Audio Reconfiguration 353 ~~~~~~~~~~~~~~~~~~~~~~~~ 354 This is an experimental feature to allow you re-configure the HD-audio 355 codec dynamically without reloading the driver. The following sysfs 356 files are available under each codec-hwdep device directory (e.g. 357 /sys/class/sound/hwC0D0): 358 359 vendor_id:: 360 Shows the 32bit codec vendor-id hex number. You can change the 361 vendor-id value by writing to this file. 362 subsystem_id:: 363 Shows the 32bit codec subsystem-id hex number. You can change the 364 subsystem-id value by writing to this file. 365 revision_id:: 366 Shows the 32bit codec revision-id hex number. You can change the 367 revision-id value by writing to this file. 368 afg:: 369 Shows the AFG ID. This is read-only. 370 mfg:: 371 Shows the MFG ID. This is read-only. 372 name:: 373 Shows the codec name string. Can be changed by writing to this 374 file. 375 modelname:: 376 Shows the currently set `model` option. Can be changed by writing 377 to this file. 378 init_verbs:: 379 The extra verbs to execute at initialization. You can add a verb by 380 writing to this file. Pass three numbers: nid, verb and parameter 381 (separated with a space). 382 hints:: 383 Shows / stores hint strings for codec parsers for any use. 384 Its format is `key = value`. For example, passing `hp_detect = yes` 385 to IDT/STAC codec parser will result in the disablement of the 386 headphone detection. 387 init_pin_configs:: 388 Shows the initial pin default config values set by BIOS. 389 driver_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. 394 user_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. 400 reconfig:: 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. 405 clear:: 406 Resets the codec, removes the mixer elements and PCM stuff of the 407 specified codec, and clear all init verbs and hints. 408 409 For example, when you want to change the pin default configuration 410 value of the pin widget 0x14 to 0x9993013f, and let the driver 411 re-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 ------------------------------------------------------------------------ 416 417 418 Early Patching 419 ~~~~~~~~~~~~~~ 420 When CONFIG_SND_HDA_PATCH_LOADER=y is set, you can pass a "patch" as a 421 firmware file for modifying the HD-audio setup before initializing the 422 codec. This can work basically like the reconfiguration via sysfs in 423 the above, but it does it before the first codec configuration. 424 425 A patch file is a plain text file which looks like below: 426 427 ------------------------------------------------------------------------ 428 [codec] 429 0x12345678 0xabcd1234 2 430 431 [model] 432 auto 433 434 [pincfg] 435 0x12 0x411111f0 436 437 [verb] 438 0x20 0x500 0x03 439 0x20 0x400 0xff 440 441 [hint] 442 hp_detect = yes 443 ------------------------------------------------------------------------ 444 445 The file needs to have a line `[codec]`. The next line should contain 446 three numbers indicating the codec vendor-id (0x12345678 in the 447 example), the codec subsystem-id (0xabcd1234) and the address (2) of 448 the codec. The rest patch entries are applied to this specified codec 449 until another codec entry is given. 450 451 The `[model]` line allows to change the model name of the each codec. 452 In the example above, it will be changed to model=auto. 453 Note that this overrides the module option. 454 455 After the `[pincfg]` line, the contents are parsed as the initial 456 default pin-configurations just like `user_pin_configs` sysfs above. 457 The values can be shown in user_pin_configs sysfs file, too. 458 459 Similarly, the lines after `[verb]` are parsed as `init_verbs` 460 sysfs entries, and the lines after `[hint]` are parsed as `hints` 461 sysfs entries, respectively. 462 463 Another example to override the codec vendor id from 0x12345678 to 464 0xdeadbeef is like below: 465 ------------------------------------------------------------------------ 466 [codec] 467 0x12345678 0xabcd1234 2 468 469 [vendor_id] 470 0xdeadbeef 471 ------------------------------------------------------------------------ 472 473 In the similar way, you can override the codec subsystem_id via 474 `[subsystem_id]`, the revision id via `[revision_id]` line. 475 Also, the codec chip name can be rewritten via `[chip_name]` line. 476 ------------------------------------------------------------------------ 477 [codec] 478 0x12345678 0xabcd1234 2 479 480 [subsystem_id] 481 0xffff1111 482 483 [revision_id] 484 0x10 485 486 [chip_name] 487 My-own NEWS-0002 488 ------------------------------------------------------------------------ 489 490 The hd-audio driver reads the file via request_firmware(). Thus, 491 a patch file has to be located on the appropriate firmware path, 492 typically, /lib/firmware. For example, when you pass the option 493 `patch=hda-init.fw`, the file /lib/firmware/hda-init-fw must be 494 present. 495 496 The patch module option is specific to each card instance, and you 497 need to give one file name for each instance, separated by commas. 498 For example, if you have two cards, one for an on-board analog and one 499 for an HDMI video board, you may pass patch option like below: 500 ------------------------------------------------------------------------ 501 options snd-hda-intel patch=on-board-patch,hdmi-patch 502 ------------------------------------------------------------------------ 503 504 505 Power-Saving 506 ~~~~~~~~~~~~ 507 The power-saving is a kind of auto-suspend of the device. When the 508 device is inactive for a certain time, the device is automatically 509 turned off to save the power. The time to go down is specified via 510 `power_save` module option, and this option can be changed dynamically 511 via sysfs. 512 513 The power-saving won't work when the analog loopback is enabled on 514 some codecs. Make sure that you mute all unneeded signal routes when 515 you want the power-saving. 516 517 The power-saving feature might cause audible click noises at each 518 power-down/up depending on the device. Some of them might be 519 solvable, but some are hard, I'm afraid. Some distros such as 520 openSUSE enables the power-saving feature automatically when the power 521 cable is unplugged. Thus, if you hear noises, suspect first the 522 power-saving. See /sys/module/snd_hda_intel/parameters/power_save to 523 check the current value. If it's non-zero, the feature is turned on. 524 525 526 Development Tree 527 ~~~~~~~~~~~~~~~~ 528 The latest development codes for HD-audio are found on sound git tree: 529 530 - git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6.git 531 532 The master branch or for-next branches can be used as the main 533 development branches in general while the HD-audio specific patches 534 are committed in topic/hda branch. 535 536 If you are using the latest Linus tree, it'd be better to pull the 537 above GIT tree onto it. If you are using the older kernels, an easy 538 way to try the latest ALSA code is to build from the snapshot 539 tarball. There are daily tarballs and the latest snapshot tarball. 540 All can be built just like normal alsa-driver release packages, that 541 is, installed via the usual spells: configure, make and make 542 install(-modules). See INSTALL in the package. The snapshot tarballs 543 are found at: 544 545 - ftp://ftp.kernel.org/pub/linux/kernel/people/tiwai/snapshot/ 546 547 548 Sending a Bug Report 549 ~~~~~~~~~~~~~~~~~~~~ 550 If any model or module options don't work for your device, it's time 551 to send a bug report to the developers. Give the following in your 552 bug report: 553 554 - Hardware vendor, product and model names 555 - Kernel version (and ALSA-driver version if you built externally) 556 - `alsa-info.sh` output; run with `--no-upload` option. See the 557 section below about alsa-info 558 559 If it's a regression, at best, send alsa-info outputs of both working 560 and non-working kernels. This is really helpful because we can 561 compare the codec registers directly. 562 563 Send a bug report either the followings: 564 565 kernel-bugzilla:: 566 http://bugme.linux-foundation.org/ 567 alsa-devel ML:: 568 alsa-devel[AT]alsa-project[DOT]org 569 570 571 DEBUG TOOLS 572 ----------- 573 574 This section describes some tools available for debugging HD-audio 575 problems. 576 577 alsa-info 578 ~~~~~~~~~ 579 The script `alsa-info.sh` is a very useful tool to gather the audio 580 device information. You can fetch the latest version from: 581 582 - http://www.alsa-project.org/alsa-info.sh 583 584 Run this script as root, and it will gather the important information 585 such as the module lists, module parameters, proc file contents 586 including the codec proc files, mixer outputs and the control 587 elements. As default, it will store the information onto a web server 588 on alsa-project.org. But, if you send a bug report, it'd be better to 589 run with `--no-upload` option, and attach the generated file. 590 591 There are some other useful options. See `--help` option output for 592 details. 593 594 When a probe error occurs or when the driver obviously assigns a 595 mismatched model, it'd be helpful to load the driver with 596 `probe_only=1` option (at best after the cold reboot) and run 597 alsa-info at this state. With this option, the driver won't configure 598 the mixer and PCM but just tries to probe the codec slot. After 599 probing, the proc file is available, so you can get the raw codec 600 information before modified by the driver. Of course, the driver 601 isn't usable with `probe_only=1`. But you can continue the 602 configuration via hwdep sysfs file if hda-reconfig option is enabled. 603 604 605 hda-verb 606 ~~~~~~~~ 607 hda-verb is a tiny program that allows you to access the HD-audio 608 codec directly. You can execute a raw HD-audio codec verb with this. 609 This program accesses the hwdep device, thus you need to enable the 610 kernel config `CONFIG_SND_HDA_HWDEP=y` beforehand. 611 612 The hda-verb program takes four arguments: the hwdep device file, the 613 widget NID, the verb and the parameter. When you access to the codec 614 on the slot 2 of the card 0, pass /dev/snd/hwC0D2 to the first 615 argument, typically. (However, the real path name depends on the 616 system.) 617 618 The second parameter is the widget number-id to access. The third 619 parameter can be either a hex/digit number or a string corresponding 620 to a verb. Similarly, the last parameter is the value to write, or 621 can be a string for the parameter type. 622 623 ------------------------------------------------------------------------ 624 % hda-verb /dev/snd/hwC0D0 0x12 0x701 2 625 nid = 0x12, verb = 0x701, param = 0x2 626 value = 0x0 627 628 % hda-verb /dev/snd/hwC0D0 0x0 PARAMETERS VENDOR_ID 629 nid = 0x0, verb = 0xf00, param = 0x0 630 value = 0x10ec0262 631 632 % hda-verb /dev/snd/hwC0D0 2 set_a 0xb080 633 nid = 0x2, verb = 0x300, param = 0xb080 634 value = 0x0 635 ------------------------------------------------------------------------ 636 637 Although you can issue any verbs with this program, the driver state 638 won't be always updated. For example, the volume values are usually 639 cached in the driver, and thus changing the widget amp value directly 640 via hda-verb won't change the mixer value. 641 642 The hda-verb program is found in the ftp directory: 643 644 - ftp://ftp.kernel.org/pub/linux/kernel/people/tiwai/misc/ 645 646 Also a git repository is available: 647 648 - git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/hda-verb.git 649 650 See README file in the tarball for more details about hda-verb 651 program. 652 653 654 hda-analyzer 655 ~~~~~~~~~~~~ 656 hda-analyzer provides a graphical interface to access the raw HD-audio 657 control, based on pyGTK2 binding. It's a more powerful version of 658 hda-verb. The program gives you an easy-to-use GUI stuff for showing 659 the widget information and adjusting the amp values, as well as the 660 proc-compatible output. 661 662 The hda-analyzer: 663 664 - http://git.alsa-project.org/?p=alsa.git;a=tree;f=hda-analyzer 665 666 is a part of alsa.git repository in alsa-project.org: 667 668 - git://git.alsa-project.org/alsa.git 669 670 Codecgraph 671 ~~~~~~~~~~ 672 Codecgraph is a utility program to generate a graph and visualizes the 673 codec-node connection of a codec chip. It's especially useful when 674 you analyze or debug a codec without a proper datasheet. The program 675 parses the given codec proc file and converts to SVG via graphiz 676 program. 677 678 The tarball and GIT trees are found in the web page at: 679 680 - http://helllabs.org/codecgraph/ 681 682 683 hda-emu 684 ~~~~~~~ 685 hda-emu is an HD-audio emulator. The main purpose of this program is 686 to debug an HD-audio codec without the real hardware. Thus, it 687 doesn't emulate the behavior with the real audio I/O, but it just 688 dumps the codec register changes and the ALSA-driver internal changes 689 at probing and operating the HD-audio driver. 690 691 The program requires a codec proc-file to simulate. Get a proc file 692 for the target codec beforehand, or pick up an example codec from the 693 codec proc collections in the tarball. Then, run the program with the 694 proc file, and the hda-emu program will start parsing the codec file 695 and simulates the HD-audio driver: 696 697 ------------------------------------------------------------------------ 698 % hda-emu codecs/stac9200-dell-d820-laptop 699 # Parsing.. 700 hda_codec: Unknown model for STAC9200, using BIOS defaults 701 hda_codec: pin nid 08 bios pin config 40c003fa 702 .... 703 ------------------------------------------------------------------------ 704 705 The program gives you only a very dumb command-line interface. You 706 can get a proc-file dump at the current state, get a list of control 707 (mixer) elements, set/get the control element value, simulate the PCM 708 operation, the jack plugging simulation, etc. 709 710 The package is found in: 711 712 - ftp://ftp.kernel.org/pub/linux/kernel/people/tiwai/misc/ 713 714 A git repository is available: 715 716 - git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/hda-emu.git 717 718 See README file in the tarball for more details about hda-emu 719 program.