What is hda in linux

Frequent question: What does SDA stand for in Linux?

The term sd stands for SCSI disk, that is to say, it means Small Computer System Interface disk. So, sda means the first SCSI hard disk. Likewise,/hda, the individual partition in the disk takes names as sda1, sda2, etc.. The active partition is indicated by an * in the middle column.

What is SDA SDB and SDC in Linux?

The first hard drive detected by a Linux system carries the sda label. In numerical terms, it is hard drive 0 (zero; counting begins from 0, not 1). The second hard drive is sdb, the third drive, sdc, etc. In the screenshot below, there are two hard drives detected by the installer – sda and sdb.

What is the difference between SDA and HDA in Linux?

If you’re talking about drives under Linux, then hda (and hdb, hdc, etc.) are IDE/ATA-1 drives whereas sda (and scb, etc.) are SCSI or SATA drives. You’ll still see the IDE drives floating around but most new systems (and new drives) are SATA or SCSI.

What is the difference between SDA and SDB in Linux?

dev/sda – The first SCSI disk SCSI ID address-wise. dev/sdb – The second SCSI disk address-wise and so on. … dev/hdb – The slave disk on IDE primary controller.

How do I know which disk is SDA?

The disk names in Linux are alphabetical. /dev/sda is the first hard drive (the primary master), /dev/sdb is the second etc. The numbers refer to partitions, so /dev/sda1 is the first partition of the first drive.

What is SDA SDB Linux?

Linux disks and partition names may be different from other operating systems. … The first hard disk detected is named /dev/sda . The second hard disk detected is named /dev/sdb , and so on. The first SCSI CD-ROM is named /dev/scd0 , also known as /dev/sr0 .

How do I find the SDA Linux?

View Specific Disk Partition in Linux

To view all partitions of specific hard disk use the option ‘-l’ with device name. For example, the following command will display all disk partitions of device /dev/sda. If you’ve different device names, simple write device name as /dev/sdb or /dev/sdc.

What is SDA in computer?

Technology. /dev/sda, the first mass-storage disk in Unix-like operating systems. Screen Design Aid, a utility program used by midrange IBM computer systems. Scratch drive actuator, converts electrical energy into motion. Serial Data Signal of an I²C electronic bus.

What is Dev SDA and Dev SDB?

dev/sda – The first SCSI disk SCSI ID address-wise. dev/sdb – The second SCSI disk address-wise and so on. dev/scd0 or /dev/sr0 – The first SCSI CD-ROM.

What is mounting in Linux?

Mounting is the attaching of an additional filesystem to the currently accessible filesystem of a computer. … Any original contents of a directory that is used as a mount point become invisible and inaccessible while the filesystem is still mounted.

What is a device in Linux?

Linux Devices. In Linux various special files can be found under the directory /dev . These files are called device files and behave unlike ordinary files. These files are an interface to the actual driver (part of the Linux kernel) which in turn accesses the hardware. …

What does TTY mean in Linux?

The tty command of terminal basically prints the file name of the terminal connected to standard input. tty is short of teletype, but popularly known as a terminal it allows you to interact with the system by passing on the data (you input) to the system, and displaying the output produced by the system.

What are Linux partitions?

Creating disk partitions enables you to split your hard drive into multiple sections that act independently. In Linux, users must structure storage devices (USB and hard drives) before using them. Partitioning is also useful when you are installing multiple operating systems on a single machine.

How do I check partitions?

Locate the disk you want to check in the Disk Management window. Right-click it and select “Properties.” Click over to the “Volumes” tab. To the right of “Partition style,” you’ll see either “Master Boot Record (MBR)” or “GUID Partition Table (GPT),” depending on which the disk is using.

How do I view partitions?

To see all of your partitions, right-click the Start button and select Disk Management. When you look at the top half of the window, you might discover that these unlettered and possibly unwanted partitions appear to be empty. Now you really know it’s wasted space!

Where are unmounted drives in Linux?

To address the listing of the unmounted partitions part, there are several ways – lsblk , fdisk , parted , blkid . lines which have first column starting with letter s (because that’s how drives typically are named) and ending with a number (which represent partitions).

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What is HDB in Linux?

hdb-Primary slave PATA hard disk.

What is SDA and HDA in Linux?

The term sd stands for SCSI disk, that is to say, it means Small Computer System Interface disk. So, sda means the first SCSI hard disk. Likewise,/hda, the individual partition in the disk takes names as sda1, sda2, etc.. … The middle column refers to the “Status” of that particular partition.

What is the primary master PATA hard disk?

Chapter 2 Installing Linux

Question	Answer
Types of PATA hard disk configurations.	Primary master PATA hard disk (hda) Primary slave PATA hard disk (hdb) Secondary master PATA hard disk (hdc) Secondary slave PATA hard disk (hdd)
Default command-line interface in Linux.	BASH (Bourne Again Shell)

What is SDA and SDB in Linux?

Linux disks and partition names may be different from other operating systems. … The first hard disk detected is named /dev/sda . The second hard disk detected is named /dev/sdb , and so on. The first SCSI CD-ROM is named /dev/scd0 , also known as /dev/sr0 .

How do I check my hard drive Linux?

Try the following commands for SCSI and hardware RAID based devices:

1. sdparm Command – fetch SCSI / SATA device information.
2. scsi_id Command – queries a SCSI device via the SCSI INQUIRY vital product data (VPD).
3. Use smartctl To Check Disk Behind Adaptec RAID Controllers.
4. Use smartctl Check Hard Disk Behind 3Ware RAID Card.

What is the difference between SDA and SDB?

dev/sda – The first SCSI disk SCSI ID address-wise. dev/sdb – The second SCSI disk address-wise and so on. … dev/hdb – The slave disk on IDE primary controller.

What is mmcblk0 in Linux?

mmcblk0 is the whole disk (starting from the boot sector and containing the partition table) and mmcblk0p1 is the first partition. There is no way mmcblk0 contains “old” data. –

What is the default shell in Linux called?

Bash (/bin/bash) is a popular shell on most if not all Linux systems, and it’s normally the default shell for user accounts. There are several reasons for changing a user’s shell in Linux including the following: To block or disable normal user logins in Linux using a nologin shell.

What is MBR in hard disk?

A master boot record (MBR) is a special type of boot sector at the very beginning of partitioned computer mass storage devices like fixed disks or removable drives intended for use with IBM PC-compatible systems and beyond.

Which type of drives is named first when names are assigned?

MS-DOS/PC DOS since version 5.0, and later operating systems, assigns drive letters according to the following algorithm: Assign the drive letter A: to the first floppy disk drive (drive 0), and B: to the second floppy disk drive (drive 1).

How do I know which disk is SDA?

The disk names in Linux are alphabetical. /dev/sda is the first hard drive (the primary master), /dev/sdb is the second etc. The numbers refer to partitions, so /dev/sda1 is the first partition of the first drive.

How do I find the SDA Linux?

View Specific Disk Partition in Linux

To view all partitions of specific hard disk use the option ‘-l’ with device name. For example, the following command will display all disk partitions of device /dev/sda. If you’ve different device names, simple write device name as /dev/sdb or /dev/sdc.

What is mount on Linux?

The mount command attaches the filesystem of an external device to the filesystem of a system. It instructs the operating system that filesystem is ready to use and associate it with a particular point in the system’s hierarchy. Mounting will make files, directories and devices available to the users.

How do I list all drives in Linux?

Listing Hard Drives in Linux

1. df. The df command in Linux is probably one of the most commonly used. …
2. fdisk. fdisk is another common option among sysops. …
3. lsblk. This one is a little more sophisticated but gets the job done as it lists all block devices. …
4. cfdisk. …
5. parted. …
6. sfdisk.

How do I find storage in Linux?

How to check free disk space in Linux

1. df. The df command stands for “disk-free,” and shows available and used disk space on the Linux system. …
2. du. The Linux Terminal. …
3. ls -al. ls -al lists the entire contents, along with their size, of a particular directory. …
4. stat. …
5. fdisk -l.

How do I find RAM in Linux?

1. Open the command line.
2. Type the following command: grep MemTotal /proc/meminfo.
3. You should see something similar to the following as output: MemTotal: 4194304 kB.
4. This is your total available memory.

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Question: What is Dev HDA Linux?

What is /dev/hda in Linux? /dev/hda is the master IDE(Integrated Drive Electronics) drive on the primary IDE controller. Linux takes the first hard disk as a whole hard disk and it represents it by /dev/hda. The individual partitions in the disk take on names like hda1, hda2, and so forth.

What is the dev folder in Linux?

/dev is the location of special or device files. It is a very interesting directory that highlights one important aspect of the Linux filesystem – everything is a file or a directory.

What is Dev SD?

You will see something like /dev/sda, /dev/sdb, /dev/sdc, … etc. instead. The dev is short for device. The sd was short for Small Computer System Interface (SCSI) mass-storage driver.

What is Dev SDA and Dev SDB?

dev/sda – The first SCSI disk SCSI ID address-wise. dev/sdb – The second SCSI disk address-wise and so on. dev/scd0 or /dev/sr0 – The first SCSI CD-ROM.

What is Dev VDA Linux?

/dev/vda is the first disk using the virtualization-aware disk driver. The performance should be much better, as the hypervisor doesn’t have to emulate some hardware interface. If the disk has been exposed to your VM under both interfaces, you should prefer /dev/vda as it’ll almost certainly be faster.

What is MNT in Linux?

The /mnt directory and its subdirectories are intended for use as the temporary mount points for mounting storage devices, such as CDROMs, floppy disks and USB (universal serial bus) key drives. /mnt is a standard subdirectory of the root directory on Linux and other Unix-like operating systems, along with directories …

Where are device files stored in Linux?

All Linux device files are located in the /dev directory, which is an integral part of the root (/) filesystem because these device files must be available to the operating system during the boot process.

What does SD mean in Linux?

The term sd stands for SCSI disk, that is to say, it means Small Computer System Interface disk. So, sda means the first SCSI hard disk. Likewise,/hda, the individual partition in the disk takes names as sda1, sda2, etc.. The active partition is indicated by an * in the middle column.

What is the difference between Dev SDA and Dev sda1?

The disk names in Linux are alphabetical. /dev/sda is the first hard drive (the primary master), /dev/sdb is the second etc. The numbers refer to partitions, so /dev/sda1 is the first partition of the first drive.

What is Lsblk?

lsblk lists information about all available or the specified block devices. The lsblk command reads the sysfs filesystem and udev db to gather information. … The command prints all block devices (except RAM disks) in a tree-like format by default. Use lsblk –help to get a list of all available columns.

What is the difference between SDA and HDA in Linux?

If you’re talking about drives under Linux, then hda (and hdb, hdc, etc.) are IDE/ATA-1 drives whereas sda (and scb, etc.) are SCSI or SATA drives. You’ll still see the IDE drives floating around but most new systems (and new drives) are SATA or SCSI.

What is Dev loop0 Ubuntu?

/dev/loop* are loop devices making plain files accessible as block devices. They have nothing to do with RAM occupation. They are typically used for mounting disk images, in your case apparently for Ubuntu Snap.

How do I know if I have Dev sda1?

To view all partitions of specific hard disk use the option ‘-l’ with device name. For example, the following command will display all disk partitions of device /dev/sda. If you’ve different device names, simple write device name as /dev/sdb or /dev/sdc.

What is the difference between SYS and Proc?

what is the actual difference between /sys and /proc directories? Roughly, proc exposes process information and general kernel data structures to userland. sys exposes kernel data structures that describe hardware (but also filesystems, SELinux, modules etc).

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More Notes on HD-Audio Driver¶

General¶

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 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. 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 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 functionality is fairly limited until now. Instead of the generic parser, usually the codec-specific parser (coded in patch_*.c) is used for the codec-specific implementations. The details about the codec-specific problems are explained in the later sections.

If you are interested in the deep debugging of HD-audio, read the HD-audio specification at first. The specification is found on Intel’s web page, for example:

HD-Audio Controller¶

DMA-Position Problem¶

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 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. position_fix=3 means to use a combination of both methods, needed for some VIA controllers. The capture stream position is corrected by comparing both LPIB and position-buffer values. position_fix=4 is another combination available for all controllers, and uses LPIB for the playback and the position-buffer for the capture streams. 0 is the default value for all other controllers, 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 processing the data on the buffer. This caused a lot of problems, for example, with ALSA dmix or JACK. Since 2.6.27 kernel, the driver puts an artificial delay to the wake up timing. This delay is controlled via bdl_pos_adj option.

When bdl_pos_adj is a negative value (as default), it’s assigned to an appropriate value depending on the controller chip. For Intel 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 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 destructs the further communication with the codec chips. The symptom appears usually as error messages like:

The first line is a warning, and this is usually relatively harmless. It means that the codec response isn’t notified via an IRQ. The driver uses explicit polling method to read the response. It gives very slight CPU overhead, but you’d unlikely notice it.

The second line is, however, a fatal error. If this happens, usually it means that something is really wrong. Most likely you are accessing a non-existing codec slot.

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 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¶

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 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:

Meanwhile, in the earlier versions, you would see a message like:

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 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 (or recently called as “fix-up”) 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 with the correct pin setup, etc. Thus, if you have a newer machine with a slightly different PCI SSID (or codec 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 (and codec-) 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/hd-audio/models.rst 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 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.

There are a few special model option values:

• when ‘nofixup’ is passed, the device-specific fixups in the codec parser are skipped.
• when generic is passed, the codec-specific parser is skipped and only the generic parser is used.

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 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 (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.

Another related problem is the automatic mute of speaker output by headphone plugging. This feature is implemented in most cases, but not on every preset model or codec-support code.

In anyway, try a different model option if you have such a problem. Some other models may match better and give you more matching functionality. If none of the available models works, send a bug report. See the bug report section for details.

If you are masochistic enough to debug the driver problem, note the following:

• The speaker (and the headphone, too) output often requires the 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) 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 analog pin. See patch_sigmatel.c.
• Very rare but some devices don’t accept the pin-detection verb until triggered. Issuing GET_PIN_SENSE verb (0xf09) may result in the codec-communication stall. Some examples are found in patch_realtek.c.

Capture Problems¶

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 – 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 recording from CD input won’t work in many cases although the driver 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 because of my laziness but mostly lack of testers. Feel free to submit the improvement patch to the author.

Direct Debugging¶

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” section.

Other Issues¶

Kernel Configuration¶

In general, I recommend you to enable the sound debug option, CONFIG_SND_DEBUG=y , no matter whether you are debugging or not. This enables snd_printd() macro and others, and you’ll get additional kernel messages at probing.

In addition, you can enable CONFIG_SND_DEBUG_VERBOSE=y . But this will give you far more messages. Thus turn this on only when you are sure to want it.

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 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 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 the corresponding hwdep directory. See “HD-audio reconfiguration” section below.

CONFIG_SND_HDA_POWER_SAVE option enables the power-saving feature. See “Power-saving” section below.

Codec Proc-File¶

The codec proc-file is a treasure-chest for debugging HD-audio. It shows most of useful information of each codec widget.

The proc file is located in /proc/asound/card*/codec#*, one file per each codec slot. You can know the codec vendor, product id and names, the type of each widget, capabilities and so on. This file, however, doesn’t show the jack sensing state, so far. This is because the jack-sensing might be depending on the trigger state.

This file will be picked up by the debug tools, and also it can be fed to the emulator as the primary codec information. See the debug tools section below.

This proc file can be also used to check whether the generic parser is used. When the generic parser is used, the vendor/product ID name will appear as “Realtek ID 0262”, instead of “Realtek ALC262”.

HD-Audio Reconfiguration¶

This is an experimental feature to allow you re-configure the HD-audio codec dynamically without reloading the driver. The following sysfs files are available under each codec-hwdep device directory (e.g. /sys/class/sound/hwC0D0):

vendor_id Shows the 32bit codec vendor-id hex number. You can change the vendor-id value by writing to this file. subsystem_id Shows the 32bit codec subsystem-id hex number. You can change the subsystem-id value by writing to this file. revision_id Shows the 32bit codec revision-id hex number. You can change the revision-id value by writing to this file. afg Shows the AFG ID. This is read-only. mfg Shows the MFG ID. This is read-only. name Shows the codec name string. Can be changed by writing to this file. modelname Shows the currently set model option. Can be changed by writing to this file. init_verbs The extra verbs to execute at initialization. You can add a verb by writing to this file. Pass three numbers: nid, verb and parameter (separated with a space). hints Shows / stores hint strings for codec parsers for any use. Its format is key = value . For example, passing jack_detect = no will disable the jack detection of the machine completely. 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 again. All the changes done by the sysfs entries above are taken into account. clear 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:

Hint Strings¶

The codec parser have several switches and adjustment knobs for matching better with the actual codec or device behavior. Many of them can be adjusted dynamically via “hints” strings as mentioned in the section above. For example, by passing jack_detect = no string via sysfs or a patch file, you can disable the jack detection, thus the codec parser will skip the features like auto-mute or mic auto-switch. As a boolean value, either yes , no , true , false , 1 or 0 can be passed.

The generic parser supports the following hints:

jack_detect (bool) specify whether the jack detection is available at all on this machine; default true inv_jack_detect (bool) indicates that the jack detection logic is inverted trigger_sense (bool) indicates that the jack detection needs the explicit call of AC_VERB_SET_PIN_SENSE verb inv_eapd (bool) indicates that the EAPD is implemented in the inverted logic pcm_format_first (bool) sets the PCM format before the stream tag and channel ID sticky_stream (bool) keep the PCM format, stream tag and ID as long as possible; default true spdif_status_reset (bool) reset the SPDIF status bits at each time the SPDIF stream is set up pin_amp_workaround (bool) the output pin may have multiple amp values single_adc_amp (bool) ADCs can have only single input amps auto_mute (bool) enable/disable the headphone auto-mute feature; default true auto_mic (bool) enable/disable the mic auto-switch feature; default true line_in_auto_switch (bool) enable/disable the line-in auto-switch feature; default false need_dac_fix (bool) limits the DACs depending on the channel count primary_hp (bool) probe headphone jacks as the primary outputs; default true multi_io (bool) try probing multi-I/O config (e.g. shared line-in/surround, mic/clfe jacks) multi_cap_vol (bool) provide multiple capture volumes inv_dmic_split (bool) provide split internal mic volume/switch for phase-inverted digital mics indep_hp (bool) provide the independent headphone PCM stream and the corresponding mixer control, if available add_stereo_mix_input (bool) add the stereo mix (analog-loopback mix) to the input mux if available add_jack_modes (bool) add “xxx Jack Mode” enum controls to each I/O jack for allowing to change the headphone amp and mic bias VREF capabilities power_save_node (bool) advanced power management for each widget, controlling the power sate (D0/D3) of each widget node depending on the actual pin and stream states power_down_unused (bool) power down the unused widgets, a subset of power_save_node, and will be dropped in future add_hp_mic (bool) add the headphone to capture source if possible hp_mic_detect (bool) enable/disable the hp/mic shared input for a single built-in mic case; default true vmaster (bool) enable/disable the virtual Master control; default true mixer_nid (int) specifies the widget NID of the analog-loopback mixer

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:

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. Passing 0 or a negative number to the first or the second value will make the check of the corresponding field be skipped. It’ll be useful for really broken devices that don’t initialize SSID properly.

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:

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.

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:

Power-Saving¶

The power-saving is a kind of auto-suspend of the device. When the device is inactive for a certain time, the device is automatically turned off to save the power. The time to go down is specified via power_save module option, and this option can be changed dynamically via sysfs.

The power-saving won’t work when the analog loopback is enabled on some codecs. Make sure that you mute all unneeded signal routes when you want the power-saving.

The power-saving feature might cause audible click noises at each power-down/up depending on the device. Some of them might be 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/module/snd_hda_intel/parameters/power_save to check the current value. If it’s non-zero, the feature is turned on.

The recent kernel supports the runtime PM for the HD-audio controller chip, too. It means that the HD-audio controller is also powered up / down dynamically. The feature is enabled only for certain controller chips like Intel LynxPoint. You can enable/disable this feature forcibly by setting power_save_controller option, which is also available at /sys/module/snd_hda_intel/parameters directory.

Tracepoints¶

The hd-audio driver gives a few basic tracepoints. hda:hda_send_cmd traces each CORB write while hda:hda_get_response traces the response from RIRB (only when read from the codec driver). hda:hda_bus_reset traces the bus-reset due to fatal error, etc, hda:hda_unsol_event traces the unsolicited events, and hda:hda_power_down and hda:hda_power_up trace the power down/up via power-saving behavior.

Enabling all tracepoints can be done like

then after some commands, you can traces from /sys/kernel/debug/tracing/trace file. For example, when you want to trace what codec command is sent, enable the tracepoint like:

Here [0:0] indicates the card number and the codec address, and val shows the value sent to the codec, respectively. The value is a packed value, and you can decode it via hda-decode-verb program included in hda-emu package below. For example, the value e3a019 is to set the left output-amp value to 25.

Development Tree¶

The latest development codes for HD-audio are found on sound git tree:

The master branch or for-next branches can be used as the main development branches in general while the development for the current and next kernels are found in for-linus and for-next branches, respectively.

Sending a Bug Report¶

If any model or module options don’t work for your device, it’s time to send a bug report to the developers. Give the following in your bug report:

• Hardware vendor, product and model names
• Kernel version (and ALSA-driver version if you built externally)
• alsa-info.sh output; run with —no-upload option. See the section below about alsa-info

If it’s a regression, at best, send alsa-info outputs of both working and non-working kernels. This is really helpful because we can compare the codec registers directly.

Send a bug report either the following:

Debug Tools¶

This section describes some tools available for debugging HD-audio problems.

alsa-info¶

The script alsa-info.sh is a very useful tool to gather the audio device information. It’s included in alsa-utils package. The latest version can be found on git repository:

The script can be fetched directly from the following URL, too:

Run this script as root, and it will gather the important information such as the module lists, module parameters, proc file contents including the codec proc files, mixer outputs and the control elements. As default, it will store the information onto a web server on alsa-project.org. But, if you send a bug report, it’d be better to run with —no-upload option, and attach the generated file.

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. 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.

The hda-verb program takes four arguments: the hwdep device file, the widget NID, the verb and the parameter. When you access to the codec on the slot 2 of the card 0, pass /dev/snd/hwC0D2 to the first argument, typically. (However, the real path name depends on the system.)

The second parameter is the widget number-id to access. The third parameter can be either a hex/digit number or a string corresponding to a verb. Similarly, the last parameter is the value to write, or can be a string for the parameter type.

Although you can issue any verbs with this program, the driver state won’t be always updated. For example, the volume values are usually cached in the driver, and thus changing the widget amp value directly via hda-verb won’t change the mixer value.

The hda-verb program is included now in alsa-tools:

Also, the old stand-alone package is found in the ftp directory:

Also a git repository is available:

See README file in the tarball for more details about hda-verb program.

hda-analyzer¶

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 an easy-to-use GUI stuff for showing the widget information and adjusting the amp values, as well as the proc-compatible output.

is a part of alsa.git repository in alsa-project.org:

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:

hda-emu¶

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 at probing and operating the HD-audio driver.

The program requires a codec proc-file to simulate. Get a proc file for the target codec beforehand, or pick up an example codec from the codec proc collections in the tarball. Then, run the program with the proc file, and the hda-emu program will start parsing the codec file and simulates the HD-audio driver:

The program gives you only a very dumb command-line interface. You can get a proc-file dump at the current state, get a list of control (mixer) elements, set/get the control element value, simulate the PCM operation, the jack plugging simulation, etc.

The program is found in the git repository below:

See README file in the repository for more details about hda-emu program.

hda-jack-retask¶

hda-jack-retask is a user-friendly GUI program to manipulate the HD-audio pin control for jack retasking. If you have a problem about the jack assignment, try this program and check whether you can get useful results. Once when you figure out the proper pin assignment, it can be fixed either in the driver code statically or via passing a firmware patch file (see “Early Patching” section).

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