HD-audio is the new standard on-board audio component on modern PCs
after AC97. Although Linux has been supporting HD-audio since long
time ago, there are often problems with new machines. A part of the
-problem is broken BIOS, and rest is the driver implementation. This
-document explains the trouble-shooting and debugging methods for the
-HD-audio hardware.
+problem is broken BIOS, and the rest is the driver implementation.
+This document explains the brief trouble-shooting and debugging
+methods for the HD-audio hardware.
The HD-audio component consists of two parts: the controller chip and
the codec chips on the HD-audio bus. Linux provides a single driver
-for all controllers, snd-hda-intel. Since the HD-audio controllers
-are supposed to be compatible, the single snd-hda-driver should work
-in most cases. But, not surprisingly, there are known bugs and issues
-specific to each controller type. The snd-hda-intel driver has a
-bunch of workarounds for these as described below.
+for all controllers, snd-hda-intel. Although the driver name contains
+a word of a well-known hardware vendor, it's not specific to it but for
+all controller chips by other companies. Since the HD-audio
+controllers are supposed to be compatible, the single snd-hda-driver
+should work in most cases. But, not surprisingly, there are known
+bugs and issues specific to each controller type. The snd-hda-intel
+driver has a bunch of workarounds for these as described below.
A controller may have multiple codecs. Usually you have one audio
-codec and optionally one modem codec. In some cases, there can be
-multiple audio codecs, e.g. for analog and digital outputs, but the
-driver might not work properly.
+codec and optionally one modem codec. In theory, there might be
+multiple audio codecs, e.g. for analog and digital outputs, and the
+driver might not work properly because of conflict of mixer elements.
+This should be fixed in future if such hardware really exists.
The snd-hda-intel driver has several different codec parsers depending
on the codec. It has a generic parser as a fallback, but this
The most common problem of the controller is the inaccurate DMA
pointer reporting. The DMA pointer for playback and capture can be
read in two ways, either via a LPIB register or via a position-buffer
-map. As default the driver tries to reads from the io-mapped
-position-buffer, and falls back to LPIB if it appears unupdated.
-However, this detection isn't perfect on some devices. In such a
-case, you can change the default method via `position_fix` option.
+map. As default the driver tries to read from the io-mapped
+position-buffer, and falls back to LPIB if the position-buffer appears
+dead. However, this detection isn't perfect on some devices. In such
+a case, you can change the default method via `position_fix` option.
`position_fix=1` means to use LPIB method explicitly.
`position_fix=2` means to use the position-buffer. 0 is the default
-value, the automatic check. If you get a problem of repeated sounds,
-this option might help.
+value, the automatic check and fallback to LPIB as described in the
+above. If you get a problem of repeated sounds, this option might
+help.
In addition to that, every controller is known to be broken regarding
the wake-up timing. It wakes up a few samples before actually
When `bdl_pos_adj` is a negative value (as default), it's assigned to
an appropriate value depending on the controller chip. For Intel
-chip, it'd be 1 while it'd be 32 for others. Usually this works.
+chips, it'd be 1 while it'd be 32 for others. Usually this works.
Only in case it doesn't work and you get warning messages, you should
-change to other values.
+change this parameter to other values.
Codec-Probing Problem
A less often but a more severe problem is the codec probing. When
BIOS reports the available codec slots wrongly, the driver gets
confused and tries to access the non-existing codec slot. This often
-results in the total screw-up, and destruct the further communication
-with the codec chips. The symptom appears usually as the error
-message like:
+results in the total screw-up, and destructs the further communication
+with the codec chips. The symptom appears usually as error messages
+like:
------------------------------------------------------------------------
- hda_intel: azx_get_response timeout, switching to polling mode: \
+ hda_intel: azx_get_response timeout, switching to polling mode:
last cmd=0x12345678
- hda_intel: azx_get_response timeout, switching to single_cmd mode: \
+ hda_intel: azx_get_response timeout, switching to single_cmd mode:
last cmd=0x12345678
------------------------------------------------------------------------
Thus, if the second error message appears, try to narrow the probed
codec slots via `probe_mask` option. It's a bitmask, and each bit
-corresponding to the codec slot. For example, to probe only the
-first slot, pass `probe_mask=1`. For the first and the third slots,
-pass `probe_mask=5` (where 5 = 1 | 4), and so on.
+corresponds to the codec slot. For example, to probe only the first
+slot, pass `probe_mask=1`. For the first and the third slots, pass
+`probe_mask=5` (where 5 = 1 | 4), and so on.
Since 2.6.29 kernel, the driver has a more robust probing method, so
this error might happen rarely, though.
+On a machine with a broken BIOS, sometimes you need to force the
+driver to probe the codec slots the hardware doesn't report for use.
+In such a case, turn the bit 8 (0x100) of `probe_mask` option on.
+Then the rest 8 bits are passed as the codec slots to probe
+unconditionally. For example, `probe_mask=0x103` will force to probe
+the codec slots 0 and 1 no matter what the hardware reports.
+
Interrupt Handling
~~~~~~~~~~~~~~~~~~
-In rare but some cases, the interrupt isn't properly handled as
-default. You would notice this by the DMA transfer error reported by
-ALSA PCM core, for example. Using MSI might help in such a case.
-Pass `enable_msi=1` option for enabling MSI.
+HD-audio driver uses MSI as default (if available) since 2.6.33
+kernel as MSI works better on some machines, and in general, it's
+better for performance. However, Nvidia controllers showed bad
+regressions with MSI (especially in a combination with AMD chipset),
+thus we disabled MSI for them.
+
+There seem also still other devices that don't work with MSI. If you
+see a regression wrt the sound quality (stuttering, etc) or a lock-up
+in the recent kernel, try to pass `enable_msi=0` option to disable
+MSI. If it works, you can add the known bad device to the blacklist
+defined in hda_intel.c. In such a case, please report and give the
+patch back to the upstream developer.
HD-AUDIO CODEC
Model Option
~~~~~~~~~~~~
-The most common problems with the HD-audio driver is the unsupported
-codec features or the mismatched device configuration. Most of
-codec-specific code has several preset models, either to override the
-BIOS setup or to provide more comprehensive features.
+The most common problem regarding the HD-audio driver is the
+unsupported codec features or the mismatched device configuration.
+Most of codec-specific code has several preset models, either to
+override the BIOS setup or to provide more comprehensive features.
The driver checks PCI SSID and looks through the static configuration
table until any matching entry is found. If you have a new machine,
you may see a message like below:
------------------------------------------------------------------------
+ hda_codec: ALC880: BIOS auto-probing.
+------------------------------------------------------------------------
+Meanwhile, in the earlier versions, you would see a message like:
+------------------------------------------------------------------------
hda_codec: Unknown model for ALC880, trying auto-probe from BIOS...
------------------------------------------------------------------------
-Even if you such a message, DON'T PANIC. Take a deep breath (and keep
-your towel). First of all, it's an informational message, no warning,
-no error. This means that the PCI SSID of your device isn't listed in
-the known preset model list. But, this doesn't mean that the driver
-is broken. Many codec-driver provides the automatic configuration
-based on the BIOS setup.
+Even if you see such a message, DON'T PANIC. Take a deep breath and
+keep your towel. First of all, it's an informational message, no
+warning, no error. This means that the PCI SSID of your device isn't
+listed in the known preset model (white-)list. But, this doesn't mean
+that the driver is broken. Many codec-drivers provide the automatic
+configuration mechanism based on the BIOS setup.
The HD-audio codec has usually "pin" widgets, and BIOS sets the default
configuration of each pin, which indicates the location, the
connection type, the jack color, etc. The HD-audio driver can guess
the right connection judging from these default configuration values.
-However -- some codec support codes, such as patch_analog.c, don't
+However -- some codec-support codes, such as patch_analog.c, don't
support the automatic probing (yet as of 2.6.28). And, BIOS is often,
yes, pretty often broken. It sets up wrong values and screws up the
driver.
-The preset model is provided basically to override such a situation.
-When the matching preset model is found in the list, the driver
+The preset model is provided basically to overcome such a situation.
+When the matching preset model is found in the white-list, the driver
assumes the static configuration of that preset and builds the mixer
-and PCM based on the static information. Thus, if you have a newer
-machine with a slightly different PCI SSID from the existing one, you
-may have a good chance to re-use the same model. You can pass the
-`model` option to specify the preset model instead of PCI SSID
-look-up.
+elements and PCM streams based on the static information. Thus, if
+you have a newer machine with a slightly different PCI SSID from the
+existing one, you may have a good chance to re-use the same model.
+You can pass the `model` option to specify the preset model instead of
+PCI SSID look-up.
What `model` option values are available depends on the codec chip.
Check your codec chip from the codec proc file (see "Codec Proc-File"
section below). It will show the vendor/product name of your codec
-chip. Then, see Documentation/sound/alsa/ALSA-Configuration.txt file.
-In the section of HD-audio driver, you can find a list of codecs and
-`model` options belonging to each codec. For example, for Realtek
+chip. Then, see Documentation/sound/alsa/HD-Audio-Models.txt file,
+the section of HD-audio driver. You can find a list of codecs
+and `model` options belonging to each codec. For example, for Realtek
ALC262 codec chip, pass `model=ultra` for devices that are compatible
with Samsung Q1 Ultra.
-Thus, the first thing you can do for any brand-new, unsupported
-HD-audio hardware is to check HD-audio codec and several different
-`model` option values. If you have a luck, some of them might suit
-with your device well.
+Thus, the first thing you can do for any brand-new, unsupported and
+non-working HD-audio hardware is to check HD-audio codec and several
+different `model` option values. If you have any luck, some of them
+might suit with your device well.
Some codecs such as ALC880 have a special model option `model=test`.
This configures the driver to provide as many mixer controls as
parser is much better than the generic parser (as now). Thus this
option is more about the debugging purpose.
-
Speaker and Headphone Output
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
One of the most frequent (and obvious) bugs with HD-audio is the
silent output from either or both of a built-in speaker and a
headphone jack. In general, you should try a headphone output at
first. A speaker output often requires more additional controls like
-the amplifier. Thus a headphone output has a slightly better chance.
+the external amplifier bits. Thus a headphone output has a slightly
+better chance.
Before making a bug report, double-check whether the mixer is set up
correctly. The recent version of snd-hda-intel driver provides mostly
-"Master" volume control as well as "Front" volume. In addition, there
-are individual "Headphone" and "Speaker" controls.
+"Master" volume control as well as "Front" volume (where Front
+indicates the front-channels). In addition, there can be individual
+"Headphone" and "Speaker" controls.
Ditto for the speaker output. There can be "External Amplifier"
switch on some codecs. Turn on this if present.
external amplifier. This can be set usually via EAPD verb or a
certain GPIO. If the codec pin supports EAPD, you have a better
chance via SET_EAPD_BTL verb (0x70c). On others, GPIO pin (mostly
- it's either GPIO0 or GPIO1) can turn on/off EAPD.
+ it's either GPIO0 or GPIO1) may turn on/off EAPD.
- Some Realtek codecs require special vendor-specific coefficients to
turn on the amplifier. See patch_realtek.c.
- IDT codecs may have extra power-enable/disable controls on each
Capture Problems
~~~~~~~~~~~~~~~~
-The capture problems are often missing setups of mixers. Thus, before
-submitting a bug report, make sure that you set up the mixer
-correctly. For example, both "Capture Volume" and "Capture Switch"
-have to be set properly in addition to the right "Capture Source" or
-"Input Source" selection. Some devices have "Mic Boost" volume or
-switch.
+The capture problems are often because of missing setups of mixers.
+Thus, before submitting a bug report, make sure that you set up the
+mixer correctly. For example, both "Capture Volume" and "Capture
+Switch" have to be set properly in addition to the right "Capture
+Source" or "Input Source" selection. Some devices have "Mic Boost"
+volume or switch.
When the PCM device is opened via "default" PCM (without pulse-audio
plugin), you'll likely have "Digital Capture Volume" control as well.
This is provided for the extra gain/attenuation of the signal in
software, especially for the inputs without the hardware volume
control such as digital microphones. Unless really needed, this
-should be set to exactly 50%, corresponding to 0dB. When you use "hw"
-PCM, i.e., a raw access PCM, this control will have no influence,
-though.
+should be set to exactly 50%, corresponding to 0dB -- neither extra
+gain nor attenuation. When you use "hw" PCM, i.e., a raw access PCM,
+this control will have no influence, though.
It's known that some codecs / devices have fairly bad analog circuits,
and the recorded sound contains a certain DC-offset. This is no bug
of the driver.
-Most of modern laptops have no analog CD-input connection. Thus, the
+Most of modern laptops have no analog CD-input connection. Thus, the
recording from CD input won't work in many cases although the driver
-provides it as the capture source.
+provides it as the capture source. Use CDDA instead.
The automatic switching of the built-in and external mic per plugging
is implemented on some codec models but not on every model. Partly
Direct Debugging
~~~~~~~~~~~~~~~~
-If no model option gives you a better result, and you are a touch guy
-to fight again the evil, try debugging via hitting the raw HD-audio
+If no model option gives you a better result, and you are a tough guy
+to fight against evil, try debugging via hitting the raw HD-audio
codec verbs to the device. Some tools are available: hda-emu and
hda-analyzer. The detailed description is found in the sections
below. You'd need to enable hwdep for using these tools. See "Kernel
-Configuration".
+Configuration" section.
OTHER ISSUES
Don't forget to turn on the appropriate `CONFIG_SND_HDA_CODEC_*`
options. Note that each of them corresponds to the codec chip, not
the controller chip. Thus, even if lspci shows the Nvidia controller,
-you may choose the option for other vendors. If you are unsure, just
-choose all yes.
+you may need to choose the option for other vendors. If you are
+unsure, just select all yes.
`CONFIG_SND_HDA_HWDEP` is a useful option for debugging the driver.
When this is enabled, the driver creates hardware-dependent devices
(one per each codec), and you have a raw access to the device via
-hda-verb program. For example, `hwC0D2` will be created for the card
-0 codec slot #2. For debug tools such as hda-verb and hda-analyzer,
-the hwdep device has to be enabled. Thus, turn this on always.
+these device files. For example, `hwC0D2` will be created for the
+codec slot #2 of the first card (#0). For debug-tools such as
+hda-verb and hda-analyzer, the hwdep device has to be enabled.
+Thus, it'd be better to turn this on always.
`CONFIG_SND_HDA_RECONFIG` is a new option, and this depends on the
hwdep option above. When enabled, you'll have some sysfs files under
to this file.
init_verbs::
The extra verbs to execute at initialization. You can add a verb by
- writing to this file. Pass tree numbers, nid, verb and parameter.
+ writing to this file. Pass three numbers: nid, verb and parameter
+ (separated with a space).
hints::
- Shows hint strings for codec parsers for any use. Right now it's
- not used.
+ Shows / stores hint strings for codec parsers for any use.
+ Its format is `key = value`. For example, passing `hp_detect = yes`
+ to IDT/STAC codec parser will result in the disablement of the
+ headphone detection.
+init_pin_configs::
+ Shows the initial pin default config values set by BIOS.
+driver_pin_configs::
+ Shows the pin default values set by the codec parser explicitly.
+ This doesn't show all pin values but only the changed values by
+ the parser. That is, if the parser doesn't change the pin default
+ config values by itself, this will contain nothing.
+user_pin_configs::
+ Shows the pin default config values to override the BIOS setup.
+ Writing this (with two numbers, NID and value) appends the new
+ value. The given will be used instead of the initial BIOS value at
+ the next reconfiguration time. Note that this config will override
+ even the driver pin configs, too.
reconfig::
Triggers the codec re-configuration. When any value is written to
this file, the driver re-initialize and parses the codec tree
Resets the codec, removes the mixer elements and PCM stuff of the
specified codec, and clear all init verbs and hints.
+For example, when you want to change the pin default configuration
+value of the pin widget 0x14 to 0x9993013f, and let the driver
+re-configure based on that state, run like below:
+------------------------------------------------------------------------
+ # echo 0x14 0x9993013f > /sys/class/sound/hwC0D0/user_pin_configs
+ # echo 1 > /sys/class/sound/hwC0D0/reconfig
+------------------------------------------------------------------------
+
+
+Early Patching
+~~~~~~~~~~~~~~
+When CONFIG_SND_HDA_PATCH_LOADER=y is set, you can pass a "patch" as a
+firmware file for modifying the HD-audio setup before initializing the
+codec. This can work basically like the reconfiguration via sysfs in
+the above, but it does it before the first codec configuration.
+
+A patch file is a plain text file which looks like below:
+
+------------------------------------------------------------------------
+ [codec]
+ 0x12345678 0xabcd1234 2
+
+ [model]
+ auto
+
+ [pincfg]
+ 0x12 0x411111f0
+
+ [verb]
+ 0x20 0x500 0x03
+ 0x20 0x400 0xff
+
+ [hint]
+ hp_detect = yes
+------------------------------------------------------------------------
+
+The file needs to have a line `[codec]`. The next line should contain
+three numbers indicating the codec vendor-id (0x12345678 in the
+example), the codec subsystem-id (0xabcd1234) and the address (2) of
+the codec. The rest patch entries are applied to this specified codec
+until another codec entry is given.
+
+The `[model]` line allows to change the model name of the each codec.
+In the example above, it will be changed to model=auto.
+Note that this overrides the module option.
+
+After the `[pincfg]` line, the contents are parsed as the initial
+default pin-configurations just like `user_pin_configs` sysfs above.
+The values can be shown in user_pin_configs sysfs file, too.
+
+Similarly, the lines after `[verb]` are parsed as `init_verbs`
+sysfs entries, and the lines after `[hint]` are parsed as `hints`
+sysfs entries, respectively.
+
+Another example to override the codec vendor id from 0x12345678 to
+0xdeadbeef is like below:
+------------------------------------------------------------------------
+ [codec]
+ 0x12345678 0xabcd1234 2
+
+ [vendor_id]
+ 0xdeadbeef
+------------------------------------------------------------------------
+
+In the similar way, you can override the codec subsystem_id via
+`[subsystem_id]`, the revision id via `[revision_id]` line.
+Also, the codec chip name can be rewritten via `[chip_name]` line.
+------------------------------------------------------------------------
+ [codec]
+ 0x12345678 0xabcd1234 2
+
+ [subsystem_id]
+ 0xffff1111
+
+ [revision_id]
+ 0x10
+
+ [chip_name]
+ My-own NEWS-0002
+------------------------------------------------------------------------
+
+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
~~~~~~~~~~~~
solvable, but some are hard, I'm afraid. Some distros such as
openSUSE enables the power-saving feature automatically when the power
cable is unplugged. Thus, if you hear noises, suspect first the
-power-saving. See /sys/modules/snd_hda_intel/parameters/power_save to
+power-saving. See /sys/module/snd_hda_intel/parameters/power_save to
check the current value. If it's non-zero, the feature is turned on.
+Development Tree
+~~~~~~~~~~~~~~~~
+The latest development codes for HD-audio are found on sound git tree:
+
+- git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6.git
+
+The master branch or for-next branches can be used as the main
+development branches in general while the HD-audio specific patches
+are committed in topic/hda branch.
+
+If you are using the latest Linus tree, it'd be better to pull the
+above GIT tree onto it. If you are using the older kernels, an easy
+way to try the latest ALSA code is to build from the snapshot
+tarball. There are daily tarballs and the latest snapshot tarball.
+All can be built just like normal alsa-driver release packages, that
+is, installed via the usual spells: configure, make and make
+install(-modules). See INSTALL in the package. The snapshot tarballs
+are found at:
+
+- ftp://ftp.kernel.org/pub/linux/kernel/people/tiwai/snapshot/
+
+
Sending a Bug Report
~~~~~~~~~~~~~~~~~~~~
If any model or module options don't work for your device, it's time
There are some other useful options. See `--help` option output for
details.
+When a probe error occurs or when the driver obviously assigns a
+mismatched model, it'd be helpful to load the driver with
+`probe_only=1` option (at best after the cold reboot) and run
+alsa-info at this state. With this option, the driver won't configure
+the mixer and PCM but just tries to probe the codec slot. After
+probing, the proc file is available, so you can get the raw codec
+information before modified by the driver. Of course, the driver
+isn't usable with `probe_only=1`. But you can continue the
+configuration via hwdep sysfs file if hda-reconfig option is enabled.
+Using `probe_only` mask 2 skips the reset of HDA codecs (use
+`probe_only=3` as module option). The hwdep interface can be used
+to determine the BIOS codec initialization.
+
hda-verb
~~~~~~~~
hda-verb is a tiny program that allows you to access the HD-audio
-codec directly. It executes a HD-audio codec verb directly.
+codec directly. You can execute a raw HD-audio codec verb with this.
This program accesses the hwdep device, thus you need to enable the
kernel config `CONFIG_SND_HDA_HWDEP=y` beforehand.
~~~~~~~~~~~~
hda-analyzer provides a graphical interface to access the raw HD-audio
control, based on pyGTK2 binding. It's a more powerful version of
-hda-verb. The program gives you a easy-to-use GUI stuff for showing
+hda-verb. The program gives you an easy-to-use GUI stuff for showing
the widget information and adjusting the amp values, as well as the
proc-compatible output.
-The hda-analyzer is a part of alsa.git repository in
-alsa-project.org:
+The hda-analyzer:
- http://git.alsa-project.org/?p=alsa.git;a=tree;f=hda-analyzer
+is a part of alsa.git repository in alsa-project.org:
+
+- git://git.alsa-project.org/alsa.git
+
+Codecgraph
+~~~~~~~~~~
+Codecgraph is a utility program to generate a graph and visualizes the
+codec-node connection of a codec chip. It's especially useful when
+you analyze or debug a codec without a proper datasheet. The program
+parses the given codec proc file and converts to SVG via graphiz
+program.
+
+The tarball and GIT trees are found in the web page at:
+
+- http://helllabs.org/codecgraph/
+
hda-emu
~~~~~~~
-hda-emu is a HD-audio emulator. The main purpose of this program is
+hda-emu is an HD-audio emulator. The main purpose of this program is
to debug an HD-audio codec without the real hardware. Thus, it
doesn't emulate the behavior with the real audio I/O, but it just
dumps the codec register changes and the ALSA-driver internal changes
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff