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diff --git a/static/freebsd/man4/pcm.4 3.html b/static/freebsd/man4/pcm.4 3.html new file mode 100644 index 00000000..839d7ab8 --- /dev/null +++ b/static/freebsd/man4/pcm.4 3.html @@ -0,0 +1,541 @@ +<table class="head"> + <tr> + <td class="head-ltitle">SOUND(4)</td> + <td class="head-vol">Device Drivers Manual</td> + <td class="head-rtitle">SOUND(4)</td> + </tr> +</table> +<div class="manual-text"> +<section class="Sh"> +<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1> +<p class="Pp"><code class="Nm">sound</code>, <code class="Nm">pcm</code>, + <code class="Nm">snd</code> — + <span class="Nd"><span class="Ux">FreeBSD</span> PCM audio device + infrastructure</span></p> +</section> +<section class="Sh"> +<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1> +<p class="Pp">To compile this driver into the kernel, place the following line + in your kernel configuration file:</p> +<div class="Bd Pp Bd-indent"><code class="Cd">device sound</code></div> +</section> +<section class="Sh"> +<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1> +<p class="Pp">The <code class="Nm">sound</code> driver is the main component of + the <span class="Ux">FreeBSD</span> sound system. It works in conjunction + with a bridge device driver on supported devices and provides PCM audio + record and playback once it attaches. Each bridge device driver supports a + specific set of audio chipsets and needs to be enabled together with the + <code class="Nm">sound</code> driver. PCI and ISA PnP audio devices identify + themselves so users are usually not required to add anything to + <span class="Pa">/boot/device.hints</span>.</p> +<p class="Pp">Some of the main features of the <code class="Nm">sound</code> + driver are: multichannel audio, per-application volume control, dynamic + mixing through virtual sound channels, true full duplex operation, bit + perfect audio, rate conversion and low latency modes.</p> +<p class="Pp">The <code class="Nm">sound</code> driver is enabled by default, + along with several bridge device drivers. Those not enabled by default can + be loaded during runtime with <a class="Xr">kldload(8)</a> or during boot + via <a class="Xr">loader.conf(5)</a>. The following bridge device drivers + are available:</p> +<p class="Pp"></p> +<ul class="Bl-bullet Bl-compact"> + <li><a class="Xr">snd_ai2s(4)</a> (enabled by default on powerpc)</li> + <li><a class="Xr">snd_als4000(4)</a></li> + <li><a class="Xr">snd_atiixp(4)</a></li> + <li><a class="Xr">snd_cmi(4)</a> (enabled by default on amd64, i386)</li> + <li><a class="Xr">snd_cs4281(4)</a></li> + <li><a class="Xr">snd_csa(4)</a> (enabled by default on amd64, i386)</li> + <li><a class="Xr">snd_davbus(4)</a> (enabled by default on powerpc)</li> + <li><a class="Xr">snd_emu10k1(4)</a></li> + <li><a class="Xr">snd_emu10kx(4)</a> (enabled by default on amd64, i386)</li> + <li><a class="Xr">snd_envy24(4)</a></li> + <li><a class="Xr">snd_envy24ht(4)</a></li> + <li><a class="Xr">snd_es137x(4)</a> (enabled by default on amd64, i386)</li> + <li><a class="Xr">snd_fm801(4)</a></li> + <li><a class="Xr">snd_hda(4)</a> (enabled by default on amd64, i386)</li> + <li><a class="Xr">snd_hdsp(4)</a></li> + <li><a class="Xr">snd_hdspe(4)</a></li> + <li><a class="Xr">snd_ich(4)</a> (enabled by default on amd64, i386)</li> + <li><a class="Xr">snd_maestro3(4)</a></li> + <li><a class="Xr">snd_neomagic(4)</a></li> + <li><a class="Xr">snd_solo(4)</a></li> + <li><a class="Xr">snd_spicds(4)</a></li> + <li><a class="Xr">snd_uaudio(4)</a> (auto-loaded on device plug)</li> + <li><a class="Xr">snd_via8233(4)</a> (enabled by default on amd64, i386)</li> + <li><a class="Xr">snd_via82c686(4)</a></li> + <li><a class="Xr">snd_vibes(4)</a></li> +</ul> +<p class="Pp">Refer to the manual page for each bridge device driver for driver + specific settings and information.</p> +<section class="Ss"> +<h2 class="Ss" id="Boot_Variables"><a class="permalink" href="#Boot_Variables">Boot + Variables</a></h2> +<p class="Pp">In general, the module <span class="Pa">snd_foo</span> corresponds + to <code class="Cd">device snd_foo</code> and can be loaded by the boot + <a class="Xr">loader(8)</a> via <a class="Xr">loader.conf(5)</a> or from the + command line using the <a class="Xr">kldload(8)</a> utility. Options which + can be specified in <span class="Pa">/boot/loader.conf</span> include:</p> +<div class="Bd-indent"> +<dl class="Bl-tag"> + <dt id="snd_driver_load"><var class="Va">snd_driver_load</var></dt> + <dd>(“<code class="Li">NO</code>”) If set to + “<code class="Li">YES</code>”, this option loads all + available drivers.</dd> + <dt id="snd_hda_load"><var class="Va">snd_hda_load</var></dt> + <dd>(“<code class="Li">NO</code>”) If set to + “<code class="Li">YES</code>”, only the Intel High + Definition Audio bridge device driver and dependent modules will be + loaded.</dd> + <dt id="snd_foo_load"><var class="Va">snd_foo_load</var></dt> + <dd>(“<code class="Li">NO</code>”) If set to + “<code class="Li">YES</code>”, load driver for card/chipset + foo.</dd> +</dl> +</div> +<p class="Pp">To define default values for the different mixer channels, set the + channel to the preferred value using hints, e.g.: + <var class="Va">hint.pcm.0.line</var>="<code class="Li">0</code>". + This will mute the input channel per default.</p> +</section> +<section class="Ss"> +<h2 class="Ss" id="Multichannel_Audio"><a class="permalink" href="#Multichannel_Audio">Multichannel + Audio</a></h2> +<p class="Pp">Multichannel audio, popularly referred to as “surround + sound” is supported and enabled by default. The + <span class="Ux">FreeBSD</span> multichannel matrix processor supports up to + 18 interleaved channels, but the limit is currently set to 8 channels (as + commonly used for 7.1 surround sound). The internal matrix mapping can + handle reduction, expansion or re-routing of channels. This provides a base + interface for related multichannel + <a class="permalink" href="#ioctl"><code class="Fn" id="ioctl">ioctl</code></a>() + support. Multichannel audio works both with and without VCHANs.</p> +<p class="Pp">Most bridge device drivers are still missing multichannel + matrixing support, but in most cases this should be trivial to implement. + Use the <var class="Va">dev.pcm.%d.[play|rec].vchanformat</var> + <a class="Xr">sysctl(8)</a> to adjust the number of channels used. The + current multichannel interleaved structure and arrangement was implemented + by inspecting various popular UNIX applications. There were no single + standard, so much care has been taken to try to satisfy each possible + scenario, despite the fact that each application has its own conflicting + standard.</p> +</section> +<section class="Ss"> +<h2 class="Ss" id="EQ"><a class="permalink" href="#EQ">EQ</a></h2> +<p class="Pp">The Parametric Software Equalizer (EQ) enables the use of + “tone” controls (bass and treble). Commonly used for ear-candy + or frequency compensation due to the vast difference in hardware quality. EQ + is disabled by default, but can be enabled with the + <var class="Va">hint.pcm.%d.eq</var> tunable.</p> +</section> +<section class="Ss"> +<h2 class="Ss" id="VCHANs"><a class="permalink" href="#VCHANs">VCHANs</a></h2> +<p class="Pp">Each device can optionally support more playback and recording + channels than physical hardware provides by using “virtual + channels” or VCHANs. VCHAN options can be configured via the + <a class="Xr">sysctl(8)</a> interface but can only be manipulated while the + device is inactive.</p> +</section> +<section class="Ss"> +<h2 class="Ss" id="VPC"><a class="permalink" href="#VPC">VPC</a></h2> +<p class="Pp"><span class="Ux">FreeBSD</span> supports independent and + individual volume controls for each active application, without touching the + master <code class="Nm">sound</code> volume. This is sometimes referred to + as Volume Per Channel (VPC). The VPC feature is enabled by default.</p> +</section> +<section class="Ss"> +<h2 class="Ss" id="Loader_Tunables"><a class="permalink" href="#Loader_Tunables">Loader + Tunables</a></h2> +<p class="Pp">The following loader tunables are used to set driver configuration + at the <a class="Xr">loader(8)</a> prompt before booting the kernel, or they + can be stored in <span class="Pa">/boot/loader.conf</span> in order to + automatically set them before booting the kernel. It is also possible to use + <a class="Xr">kenv(1)</a> to change these tunables before loading the + <code class="Nm">sound</code> driver. The following tunables can not be + changed during runtime using <a class="Xr">sysctl(8)</a>.</p> +<dl class="Bl-tag"> + <dt id="hint.pcm._d.eq"><var class="Va">hint.pcm.%d.eq</var></dt> + <dd>Set to 1 or 0 to explicitly enable (1) or disable (0) the equalizer. + Requires a driver reload if changed. Enabling this will make bass and + treble controls appear in mixer applications. This tunable is undefined by + default. Equalizing is disabled by default.</dd> + <dt id="hint.pcm._d.vpc"><var class="Va">hint.pcm.%d.vpc</var></dt> + <dd>Set to 1 or 0 to explicitly enable (1) or disable (0) the VPC feature. + This tunable is undefined by default. VPC is however enabled by + default.</dd> +</dl> +</section> +<section class="Ss"> +<h2 class="Ss" id="Runtime_Configuration"><a class="permalink" href="#Runtime_Configuration">Runtime + Configuration</a></h2> +<p class="Pp">There are a number of <a class="Xr">sysctl(8)</a> variables + available which can be modified during runtime. These values can also be + stored in <span class="Pa">/etc/sysctl.conf</span> in order to automatically + set them during the boot process. <var class="Va">hw.snd.*</var> are global + settings and <var class="Va">dev.pcm.*</var> are device specific.</p> +<dl class="Bl-tag"> + <dt id="hw.snd.compat_linux_mmap"><var class="Va">hw.snd.compat_linux_mmap</var></dt> + <dd>Linux <a class="Xr">mmap(2)</a> compatibility. The following values are + supported (default is 0): + <dl class="Bl-tag"> + <dt>-1</dt> + <dd>Force disabling/denying PROT_EXEC <a class="Xr">mmap(2)</a> + requests.</dd> + <dt>0</dt> + <dd>Auto detect proc/ABI type, allow <a class="Xr">mmap(2)</a> for Linux + applications, and deny for everything else.</dd> + <dt>1</dt> + <dd>Always allow PROT_EXEC page mappings.</dd> + </dl> + </dd> + <dt id="hw.snd.default_auto"><var class="Va">hw.snd.default_auto</var></dt> + <dd>Automatically assign the default sound unit. The following values are + supported (default is 1): + <dl class="Bl-tag"> + <dt>0</dt> + <dd>Do not assign the default sound unit automatically.</dd> + <dt>1</dt> + <dd>Use the best available sound device based on playing and recording + capabilities of the device.</dd> + <dt>2</dt> + <dd>Use the most recently attached device.</dd> + </dl> + </dd> + <dt id="hw.snd.default_unit"><var class="Va">hw.snd.default_unit</var></dt> + <dd>Default sound card for systems with multiple sound cards. When using + <a class="Xr">devfs(4)</a>, the default device for + <span class="Pa">/dev/dsp</span>. Equivalent to a symlink from + <span class="Pa">/dev/dsp</span> to + <span class="Pa">/dev/dsp</span><var class="Va">${hw.snd.default_unit}</var>.</dd> + <dt id="hw.snd.feeder_eq_exact_rate"><var class="Va">hw.snd.feeder_eq_exact_rate</var></dt> + <dd>Only certain rates are allowed for precise processing. The default + behavior is however to allow sloppy processing for all rates, even the + unsupported ones. Enable to toggle this requirement and only allow + processing for supported rates.</dd> + <dt id="hw.snd.feeder_rate_max"><var class="Va">hw.snd.feeder_rate_max</var></dt> + <dd>Maximum allowable sample rate.</dd> + <dt id="hw.snd.feeder_rate_min"><var class="Va">hw.snd.feeder_rate_min</var></dt> + <dd>Minimum allowable sample rate.</dd> + <dt id="hw.snd.feeder_rate_polyphase_max"><var class="Va">hw.snd.feeder_rate_polyphase_max</var></dt> + <dd>Adjust to set the maximum number of allowed polyphase entries during the + process of building resampling filters. Disabling polyphase resampling has + the benefit of reducing memory usage, at the expense of slower and lower + quality conversion. Only applicable when the SINC interpolator is used. + Default value is 183040. Set to 0 to disable polyphase resampling.</dd> + <dt id="hw.snd.feeder_rate_quality"><var class="Va">hw.snd.feeder_rate_quality</var></dt> + <dd>Sample rate converter quality. Default value is 1, linear interpolation. + Available options include: + <dl class="Bl-tag"> + <dt>0</dt> + <dd>Zero Order Hold, ZOH. Very fast, but with poor quality.</dd> + <dt>1</dt> + <dd>Linear interpolation. Fast, quality is subject to personal preference. + Technically the quality is poor however, due to the lack of + anti-aliasing filtering.</dd> + <dt>2</dt> + <dd>Bandlimited SINC interpolator. Implements polyphase banking to boost + the conversion speed, at the cost of memory usage, with multiple high + quality polynomial interpolators to improve the conversion accuracy. + 100% fixed point, 64bit accumulator with 32bit coefficients and high + precision sample buffering. Quality values are 100dB stopband, 8 taps + and 85% bandwidth.</dd> + <dt>3</dt> + <dd>Continuation of the bandlimited SINC interpolator, with 100dB + stopband, 36 taps and 90% bandwidth as quality values.</dd> + <dt>4</dt> + <dd>Continuation of the bandlimited SINC interprolator, with 100dB + stopband, 164 taps and 97% bandwidth as quality values.</dd> + </dl> + </dd> + <dt id="hw.snd.feeder_rate_round"><var class="Va">hw.snd.feeder_rate_round</var></dt> + <dd>Sample rate rounding threshold, to avoid large prime division at the cost + of accuracy. All requested sample rates will be rounded to the nearest + threshold value. Possible values range between 0 (disabled) and 500. + Default is 25.</dd> + <dt id="hw.snd.latency"><var class="Va">hw.snd.latency</var></dt> + <dd>Configure the buffering latency. Only affects applications that do not + explicitly request blocksize / fragments. This tunable provides finer + granularity than the <var class="Va">hw.snd.latency_profile</var> tunable. + Possible values range between 0 (lowest latency) and 10 (highest + latency).</dd> + <dt id="hw.snd.latency_profile"><var class="Va">hw.snd.latency_profile</var></dt> + <dd>Define sets of buffering latency conversion tables for the + <var class="Va">hw.snd.latency</var> tunable. A value of 0 will use a low + and aggressive latency profile which can result in possible underruns if + the application cannot keep up with a rapid irq rate, especially during + high workload. The default value is 1, which is considered a moderate/safe + latency profile.</dd> + <dt id="hw.snd.vchans_enable"><var class="Va">hw.snd.vchans_enable</var></dt> + <dd>Global VCHAN setting to enable (1) or disable (0) VCHANs. This setting can + be overridden for an individual device by using the + <var class="Va">dev.pcm.%d.[play|rec].vchans</var> tunables. Default is + enabled.</dd> + <dt id="hw.snd.report_soft_formats"><var class="Va">hw.snd.report_soft_formats</var></dt> + <dd>Controls the internal format conversion if it is available transparently + to the application software. When disabled or not available, the + application will only be able to select formats the device natively + supports.</dd> + <dt id="hw.snd.report_soft_matrix"><var class="Va">hw.snd.report_soft_matrix</var></dt> + <dd>Enable seamless channel matrixing even if the hardware does not support + it. Makes it possible to play multichannel streams even with a simple + stereo sound card.</dd> + <dt id="hw.snd.verbose"><var class="Va">hw.snd.verbose</var></dt> + <dd>Level of verbosity for the <span class="Pa">/dev/sndstat</span> device. + Higher values include more output and the highest level, four, should be + used when reporting problems. Other options include: + <dl class="Bl-tag"> + <dt>0</dt> + <dd>Installed devices and their allocated bus resources.</dd> + <dt>1</dt> + <dd>The number of playback, record, virtual channels, and flags per + device.</dd> + <dt>2</dt> + <dd>Channel information per device including the channel's current format, + speed, and pseudo device statistics such as buffer overruns and buffer + underruns.</dd> + <dt>3</dt> + <dd>File names and versions of the currently loaded sound modules.</dd> + <dt>4</dt> + <dd>Various messages intended for debugging.</dd> + </dl> + </dd> + <dt id="hw.snd.vpc_0db"><var class="Va">hw.snd.vpc_0db</var></dt> + <dd>Default value for <code class="Nm">sound</code> volume. Increase to give + more room for attenuation control. Decrease for more amplification, with + the possible cost of sound clipping.</dd> + <dt id="hw.snd.vpc_autoreset"><var class="Va">hw.snd.vpc_autoreset</var></dt> + <dd>When a channel is closed the channel volume will be reset to 0db. This + means that any changes to the volume will be lost. Enabling this will + preserve the volume, at the cost of possible confusion when applications + tries to re-open the same device.</dd> + <dt id="hw.snd.vpc_mixer_bypass"><var class="Va">hw.snd.vpc_mixer_bypass</var></dt> + <dd>The recommended way to use the VPC feature is to teach applications to use + the correct + <a class="permalink" href="#ioctl~2"><code class="Fn" id="ioctl~2">ioctl</code></a>(): + <code class="Dv">SNDCTL_DSP_GETPLAYVOL</code>, + <code class="Dv">SNDCTL_DSP_SETPLAYVOL</code>, + <code class="Dv">SNDCTL_DSP_SETRECVOL</code>, + <code class="Dv">SNDCTL_DSP_SETRECVOL</code>. This is however not always + possible. Enable this to allow applications to use their own existing + mixer logic to control their own channel volume.</dd> + <dt id="hw.snd.vpc_reset"><var class="Va">hw.snd.vpc_reset</var></dt> + <dd>Enable to restore all channel volumes back to the default value of + 0db.</dd> + <dt id="dev.pcm._d.bitperfect"><var class="Va">dev.pcm.%d.bitperfect</var></dt> + <dd>Enable or disable bitperfect mode. When enabled, channels will skip all + dsp processing, such as channel matrixing, rate converting and equalizing. + The pure <code class="Nm">sound</code> stream will be fed directly to the + hardware. If VCHANs are enabled, the bitperfect mode will use the VCHAN + format/rate as the definitive format/rate target. The recommended way to + use bitperfect mode is to disable VCHANs and enable this sysctl. Default + is disabled.</dd> + <dt id="dev.pcm._d._play_rec_.vchans"><var class="Va">dev.pcm.%d.[play|rec].vchans</var></dt> + <dd>Enable (1) or disable (0) VCHANs. Default is enabled.</dd> + <dt id="dev.pcm._d._play_rec_.vchanformat"><var class="Va">dev.pcm.%d.[play|rec].vchanformat</var></dt> + <dd>Format for VCHAN mixing. All playback paths will be converted to this + format before the mixing process begins. By default only 2 channels are + enabled. Available options include: + <dl class="Bl-tag"> + <dt>s16le:1.0</dt> + <dd>Mono.</dd> + <dt>s16le:2.0</dt> + <dd>Stereo, 2 channels (left, right).</dd> + <dt>s16le:2.1</dt> + <dd>3 channels (left, right, LFE).</dd> + <dt>s16le:3.0</dt> + <dd>3 channels (left, right, rear center).</dd> + <dt>s16le:4.0</dt> + <dd>Quadraphonic, 4 channels (front/rear left and right).</dd> + <dt>s16le:4.1</dt> + <dd>5 channels (4.0 + LFE).</dd> + <dt>s16le:5.0</dt> + <dd>5 channels (4.0 + center).</dd> + <dt>s16le:5.1</dt> + <dd>6 channels (4.0 + center + LFE).</dd> + <dt>s16le:6.0</dt> + <dd>6 channels (4.0 + front/rear center).</dd> + <dt>s16le:6.1</dt> + <dd>7 channels (6.0 + LFE).</dd> + <dt>s16le:7.1</dt> + <dd>8 channels (4.0 + center + LFE + left and right side).</dd> + </dl> + </dd> + <dt id="dev.pcm._d._play_rec_.vchanmode"><var class="Va">dev.pcm.%d.[play|rec].vchanmode</var></dt> + <dd>VCHAN format/rate selection. Available options include: + <dl class="Bl-tag"> + <dt>fixed</dt> + <dd>Channel mixing is done using fixed format/rate. Advanced operations + such as digital passthrough will not work. Can be considered as a + “legacy” mode. This is the default mode for hardware + channels which lack support for digital formats.</dd> + <dt>passthrough</dt> + <dd>Channel mixing is done using fixed format/rate, but advanced + operations such as digital passthrough also work. All channels will + produce sound as usual until a digital format playback is requested. + When this happens all other channels will be muted and the latest + incoming digital format will be allowed to pass through undisturbed. + Multiple concurrent digital streams are supported, but the latest + stream will take precedence and mute all other streams.</dd> + <dt>adaptive</dt> + <dd>Works like the “passthrough” mode, but is a bit smarter, + especially for multiple <code class="Nm">sound</code> channels with + different format/rate. When a new channel is about to start, the + entire list of virtual channels will be scanned, and the channel with + the best format/rate (usually the highest/biggest) will be selected. + This ensures that mixing quality depends on the best channel. The + downside is that the hardware DMA mode needs to be restarted, which + may cause annoying pops or clicks.</dd> + </dl> + </dd> + <dt id="dev.pcm._d._play_rec_.vchanrate"><var class="Va">dev.pcm.%d.[play|rec].vchanrate</var></dt> + <dd>Sample rate speed for VCHAN mixing. All playback paths will be converted + to this sample rate before the mixing process begins.</dd> + <dt id="dev.pcm._d.polling"><var class="Va">dev.pcm.%d.polling</var></dt> + <dd>Experimental polling mode support where the driver operates by querying + the device state on each tick using a <a class="Xr">callout(9)</a> + mechanism. Disabled by default and currently only available for a few + device drivers.</dd> +</dl> +</section> +<section class="Ss"> +<h2 class="Ss" id="Statistics"><a class="permalink" href="#Statistics">Statistics</a></h2> +<p class="Pp">Channel statistics are only kept while the device is open. So with + situations involving overruns and underruns, consider the output while the + errant application is open and running.</p> +</section> +<section class="Ss"> +<h2 class="Ss" id="IOCTL_Support"><a class="permalink" href="#IOCTL_Support">IOCTL + Support</a></h2> +<p class="Pp">The driver supports most of the OSS + <code class="Fn">ioctl</code>() functions, and most applications work + unmodified. A few differences exist, while memory mapped playback is + supported natively and in Linux emulation, memory mapped recording is not + due to VM system design. As a consequence, some applications may need to be + recompiled with a slightly modified audio module. See + <code class="In"><<a class="In">sys/soundcard.h</a>></code> for a + complete list of the supported <code class="Fn">ioctl</code>() + functions.</p> +</section> +</section> +<section class="Sh"> +<h1 class="Sh" id="FILES"><a class="permalink" href="#FILES">FILES</a></h1> +<p class="Pp">The <code class="Nm">sound</code> drivers may create the following + device nodes:</p> +<p class="Pp"></p> +<dl class="Bl-tag Bl-compact"> + <dt><span class="Pa">/dev/dsp%d</span></dt> + <dd>Audio device. The number represents the unit number of the device.</dd> + <dt><span class="Pa">/dev/dsp</span></dt> + <dd>Alias of <span class="Pa">/dev/dsp${hw.snd.default_unit}</span>. Available + only if <span class="Pa">hw.snd.basename_clone</span> is set.</dd> + <dt><span class="Pa">/dev/sndstat</span></dt> + <dd>Current <code class="Nm">sound</code> status, including all channels and + drivers.</dd> +</dl> +<p class="Pp">All <code class="Nm">sound</code> devices are listed in + <span class="Pa">/dev/sndstat</span>. Additional messages are sometimes + recorded when the device is probed and attached, these messages can be + viewed with the <a class="Xr">dmesg(8)</a> utility.</p> +</section> +<section class="Sh"> +<h1 class="Sh" id="EXAMPLES"><a class="permalink" href="#EXAMPLES">EXAMPLES</a></h1> +<p class="Pp">Use the sound metadriver to load all <code class="Nm">sound</code> + bridge device drivers at once (for example if it is unclear which the + correct driver to use is):</p> +<p class="Pp"></p> +<div class="Bd Bd-indent"><code class="Li">kldload snd_driver</code></div> +<p class="Pp">Load a specific bridge device driver, in this case the Intel High + Definition Audio driver:</p> +<p class="Pp"></p> +<div class="Bd Bd-indent"><code class="Li">kldload snd_hda</code></div> +<p class="Pp">Check the status of all detected <code class="Nm">sound</code> + devices:</p> +<p class="Pp"></p> +<div class="Bd Bd-indent"><code class="Li">cat /dev/sndstat</code></div> +<p class="Pp">Change the default sound device, in this case to the second + device. This is handy if there are multiple <code class="Nm">sound</code> + devices available:</p> +<p class="Pp"></p> +<div class="Bd Bd-indent"><code class="Li">mixer -d pcm1</code></div> +</section> +<section class="Sh"> +<h1 class="Sh" id="DIAGNOSTICS"><a class="permalink" href="#DIAGNOSTICS">DIAGNOSTICS</a></h1> +<dl class="Bl-diag"> + <dt>pcm%d:play:%d:dsp%d.p%d: play interrupt timeout, channel dead</dt> + <dd>The hardware does not generate interrupts to serve incoming (play) or + outgoing (record) data.</dd> + <dt>unsupported subdevice XX</dt> + <dd>A device node is not created properly.</dd> +</dl> +</section> +<section class="Sh"> +<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE + ALSO</a></h1> +<p class="Pp"><a class="Xr">devfs(4)</a>, <a class="Xr">snd_ai2s(4)</a>, + <a class="Xr">snd_als4000(4)</a>, <a class="Xr">snd_atiixp(4)</a>, + <a class="Xr">snd_cmi(4)</a>, <a class="Xr">snd_cs4281(4)</a>, + <a class="Xr">snd_csa(4)</a>, <a class="Xr">snd_davbus(4)</a>, + <a class="Xr">snd_emu10k1(4)</a>, <a class="Xr">snd_emu10kx(4)</a>, + <a class="Xr">snd_envy24(4)</a>, <a class="Xr">snd_envy24ht(4)</a>, + <a class="Xr">snd_es137x(4)</a>, <a class="Xr">snd_fm801(4)</a>, + <a class="Xr">snd_hda(4)</a>, <a class="Xr">snd_hdsp(4)</a>, + <a class="Xr">snd_hdspe(4)</a>, <a class="Xr">snd_ich(4)</a>, + <a class="Xr">snd_maestro3(4)</a>, <a class="Xr">snd_neomagic(4)</a>, + <a class="Xr">snd_solo(4)</a>, <a class="Xr">snd_spicds(4)</a>, + <a class="Xr">snd_t4dwave(4)</a>, <a class="Xr">snd_uaudio(4)</a>, + <a class="Xr">snd_via8233(4)</a>, <a class="Xr">snd_via82c686(4)</a>, + <a class="Xr">snd_vibes(4)</a>, <a class="Xr">device.hints(5)</a>, + <a class="Xr">loader.conf(5)</a>, <a class="Xr">dmesg(8)</a>, + <a class="Xr">kldload(8)</a>, <a class="Xr">mixer(8)</a>, + <a class="Xr">sysctl(8)</a></p> +<p class="Pp"><cite class="Rs"><span class="RsT">Cookbook formulae for audio EQ + biquad filter coefficients (Audio-EQ-Cookbook.txt), by Robert + Bristow-Johnson</span>, + <a class="RsU" href="https://www.musicdsp.org/en/latest/Filters/197-rbj-audio-eq-cookbook.html">https://www.musicdsp.org/en/latest/Filters/197-rbj-audio-eq-cookbook.html</a>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsT">Julius O'Smith's Digital Audio + Resampling</span>, + <a class="RsU" href="http://ccrma.stanford.edu/~jos/resample/">http://ccrma.stanford.edu/~jos/resample/</a>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsT">Polynomial Interpolators for + High-Quality Resampling of Oversampled Audio, by Olli Niemitalo</span>, + <a class="RsU" href="http://yehar.com/blog/wp-content/uploads/2009/08/deip.pdf">http://yehar.com/blog/wp-content/uploads/2009/08/deip.pdf</a>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsT">The OSS API</span>, + <a class="RsU" href="http://www.opensound.com/pguide/oss.pdf">http://www.opensound.com/pguide/oss.pdf</a>.</cite></p> +</section> +<section class="Sh"> +<h1 class="Sh" id="HISTORY"><a class="permalink" href="#HISTORY">HISTORY</a></h1> +<p class="Pp">The <code class="Nm">sound</code> device driver first appeared in + <span class="Ux">FreeBSD 2.2.6</span> as <code class="Nm">pcm</code>, + written by <span class="An">Luigi Rizzo</span>. It was later rewritten in + <span class="Ux">FreeBSD 4.0</span> by <span class="An">Cameron + Grant</span>. The API evolved from the VOXWARE standard which later became + OSS standard.</p> +</section> +<section class="Sh"> +<h1 class="Sh" id="AUTHORS"><a class="permalink" href="#AUTHORS">AUTHORS</a></h1> +<p class="Pp"><span class="An">Luigi Rizzo</span> + <<a class="Mt" href="mailto:luigi@iet.unipi.it">luigi@iet.unipi.it</a>> + initially wrote the <code class="Nm">pcm</code> device driver and this + manual page. <span class="An">Cameron Grant</span> + <<a class="Mt" href="mailto:gandalf@vilnya.demon.co.uk">gandalf@vilnya.demon.co.uk</a>> + later revised the device driver for <span class="Ux">FreeBSD 4.0</span>. + <span class="An">Seigo Tanimura</span> + <<a class="Mt" href="mailto:tanimura@r.dl.itc.u-tokyo.ac.jp">tanimura@r.dl.itc.u-tokyo.ac.jp</a>> + revised this manual page. It was then rewritten for <span class="Ux">FreeBSD + 5.2</span>.</p> +</section> +<section class="Sh"> +<h1 class="Sh" id="BUGS"><a class="permalink" href="#BUGS">BUGS</a></h1> +<p class="Pp">Some features of your sound card (e.g., global volume control) + might not be supported on all devices.</p> +<p class="Pp">Some audio devices might refuse to work properly unless the sample + rate is configured the same for both recording and playback, even if only + simplex is used. See the + <var class="Va">dev.pcm.%d.[play|rec].vchanrate</var> sysctls.</p> +</section> +</div> +<table class="foot"> + <tr> + <td class="foot-date">February 15, 2025</td> + <td class="foot-os">FreeBSD 15.0</td> + </tr> +</table> |