diff --git a/share/man/man4/sndstat.4 b/share/man/man4/sndstat.4 index 2fc55f0045c1..44c3f3152610 100644 --- a/share/man/man4/sndstat.4 +++ b/share/man/man4/sndstat.4 @@ -1,394 +1,394 @@ .\" .\" SPDX-License-Identifier: BSD-2-Clause .\" .\" This software was developed by Ka Ho Ng .\" under sponsorship from the FreeBSD Foundation. .\" .\" Copyright (c) 2020 The FreeBSD Foundation .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" Note: The date here should be updated whenever a non-trivial .\" change is made to the manual page. .Dd July 26, 2024 .Dt SNDSTAT 4 .Os .Sh NAME .Nm sndstat .Nd "nvlist-based PCM audio device enumeration interface" .Sh SYNOPSIS To compile the driver into the kernel, place the following lines in the kernel configuration file: .Bd -ragged -offset indent .Cd "device sound" .Ed .Sh DESCRIPTION The ioctl interface provided by .Pa /dev/sndstat device allows callers to enumerate PCM audio devices available for use. In other words, it provides means to get the list of all audio devices available to the system. .Sh IOCTLS For ioctl calls that take an argument, the following structure is used: .Bd -literal -offset indent struct sndstioc_nv_arg { size_t nbytes; void *buf; }; .Ed .Pp Here is an example of an nvlist object with explanations of the common fields: .Bd -literal -offset indent dsps (NVLIST ARRAY): 1 from_user (BOOL): FALSE nameunit (STRING): [pcm0] devnode (STRING): [dsp0] desc (STRING): [Generic (0x8086) (Analog Line-out)] pchan (NUMBER): 1 rchan (NUMBER): 0 info_play (NVLIST): min_rate (NUMBER): 48000 max_rate (NUMBER): 48000 formats (NUMBER): 16 min_chn (NUMBER): 2 max_chn (NUMBER): 2 provider_info (NVLIST): unit (NUMBER): 0 status (STRING): on hdaa0 bitperfect (BOOL): FALSE pvchan (NUMBER): 1 pvchanrate (NUMBER): 48000 pvchanformat (NUMBER): 0x00000010 rvchan (NUMBER): 0 rvchanrate (NUMBER): 48000 rvchanformat (NUMBER): 0x00000010 channel_info (NVLIST_ARRAY): 1 name (STRING): pcm0:virtual_play:dsp0.vp0 parentchan (STRING): pcm0:play:dsp0.p0 unit (NUMBER): 1 caps (NUMBER): 0x073200 latency (NUMBER): 2 rate (NUMBER): 48000 format (NUMBER): 0x201000 pid (NUMBER): 1234 comm (STRING): mpv interrupts (NUMBER): 0 feedcount (NUMBER): 0 xruns (NUMBER): 0 left_volume (NUMBER): 45 right_volume (NUMBER): 45 hwbuf_fmt (NUMBER): 0x200010 hwbuf_size (NUMBER): 0 hwbuf_blksz (NUMBER): 0 hwbuf_blkcnt (NUMBER): 0 hwbuf_free (NUMBER): 0 hwbuf_ready (NUMBER): 0 swbuf_fmt (NUMBER): 0x201000 swbuf_size (NUMBER): 16384 swbuf_blksz (NUMBER): 2048 swbuf_blkcnt (NUMBER): 8 swbuf_free (NUMBER): 16384 swbuf_ready (NUMBER): 0 feederchain (STRING): [userland -> feeder_root(0x00201000) -> feeder_format(0x00201000 -> 0x00200010) -> feeder_volume(0x00200010) -> hardware] provider (STRING): [sound(4)] .Ed .Bl -tag -width ".Dv provider_info" .It Dv from_user Whether the PCM audio device node is created by in-kernel audio subsystem or userspace providers. .It Dv nameunit The device identification in the form of subsystem plus a unit number. .It Dv devnode The PCM audio device node relative path in devfs. .It Dv desc The description of the PCM audio device. .It Dv pchan The number of playback channels supported by hardware. This can be 0 if this PCM audio device does not support playback at all. .It Dv rchan The number of recording channels supported by hardware. This can be 0 if this PCM audio device does not support recording at all. .It Dv info_play Supported configurations in playback direction. This exists only if this PCM audio device supports playback. There are a number of name/value pairs inside this field: .Bl -tag -width ".Dv min_rate" .It Dv min_rate Minimum supported sampling rate. .It Dv max_rate Maximum supported sampling rate. .It Dv formats Supported sample formats. .It Dv min_chn Minimum supported number of channels in channel layout .It Dv max_chn Maximum supported number of channels in channel layout .El .It Dv info_rec Supported configurations in recording direction. This exists only if this PCM audio device supports recording. There are a number of name/value pairs inside this field: .Bl -tag -width ".Dv min_rate" .It Dv min_rate Minimum supported sampling rate. .It Dv max_rate Maximum supported sampling rate. .It Dv formats Supported sample formats. .It Dv min_chn Minimum supported number of channels in channel layout .It Dv max_chn Maximum supported number of channels in channel layout .El .It Dv provider_info Provider-specific fields. This field may not exist if the PCM audio device is not provided by in-kernel interface. This field will not exist if the provider field is an empty string. For the .Xr sound 4 provider, there are a number of name/value pairs inside this field: .Bl -tag -width ".Dv channel_info" .It Dv unit Sound card unit. .It Dv status Status string. Usually reports the driver the device is attached on. .It Dv bitperfect Whether the sound card has bit-perfect mode enabled. .It Dv pvchan Number of playback virtual channels. .It Dv pvchanrate Playback virtual channel sample rate. .It Dv pvchanformat Playback virtual channel format. .It Dv rvchan Number of recording virtual channels. .It Dv rvchanrate Recording virtual channel sample rate. .It Dv rvchanformat Recording virtual channel format. .It Dv channel_info Channel information. There are a number of name/value pairs inside this field: .Bl -tag -width ".Dv hwbuf_blkcnt" .It Dv name Channel name. -.It Dv parenchan +.It Dv parentchan Parent channel name (e.g., in the case of virtual channels). .It Dv unit Channel unit. .It Dv caps OSS capabilities. .It Dv latency Latency. .It Dv rate Sampling rate. .It Dv format Sampling format. .It Dv pid PID of the process consuming the channel. .It Dv comm Name of the process consuming the channel. .It Dv interrupts Number of interrupts since the channel has been opened. .It Dv xruns Number of overruns/underruns, depending on channel direction. .It Dv feedcount Number of read/written bytes since the channel has been opened. .It Dv left_volume Left volume. .It Dv right_volume Right volume. .It Dv hwbuf_format Hardware buffer format. .It Dv hwbuf_size Hardware buffer size. .It Dv hwbuf_blksz Hardware buffer block size. .It Dv hwbuf_blkcnt Hardware buffer block count. .It Dv hwbuf_free Free space in hardware buffer (in bytes). .It Dv hwbuf_ready Number of bytes ready to be read/written from hardware buffer. .It Dv swbuf_format Software buffer format. .It Dv swbuf_size Software buffer size. .It Dv swbuf_blksz Software buffer block size. .It Dv swbuf_blkcnt Software buffer block count. .It Dv swbuf_free Free space in software buffer (in bytes). .It Dv swbuf_ready Number of bytes ready to be read/written from software buffer. .It Dv feederchain Channel feeder chain. .El .El .It Dv provider A string specifying the provider of the PCm audio device. .El .Pp The following ioctls are provided for use: .Bl -tag -width ".Dv SNDSTIOC_FLUSH_USER_DEVS" .It Dv SNDSTIOC_REFRESH_DEVS Drop any previously fetched PCM audio devices list snapshots. This ioctl takes no arguments. .It Dv SNDSTIOC_GET_DEVS Generate and/or return PCM audio devices list snapshots to callers. This ioctl takes a pointer to .Fa struct sndstioc_nv_arg as the first and the only argument. Callers need to provide a sufficiently large buffer to hold a serialized nvlist. If there is no existing PCM audio device list snapshot available in the internal structure of the opened sndstat. .Fa fd , a new PCM audio device list snapshot will be automatically generated. Callers have to set .Fa nbytes to either 0 or the size of buffer provided. In case .Fa nbytes is 0, the buffer size required to hold a serialized nvlist stream of current snapshot will be returned in .Fa nbytes , and .Fa buf will be ignored. Otherwise, if the buffer is not sufficiently large, the ioctl returns success, and .Fa nbytes will be set to 0. If the buffer provided is sufficiently large, .Fa nbytes will be set to the size of the serialized nvlist written to the provided buffer. Once a PCM audio device list snapshot is returned to user-space successfully, the snapshot stored in the subsystem's internal structure of the given .Fa fd will be freed. .It Dv SNDSTIOC_ADD_USER_DEVS Add a list of PCM audio devices provided by callers to .Pa /dev/sndstat device. This ioctl takes a pointer to .Fa struct sndstioc_nv_arg as the first and the only argument. Callers have to provide a buffer holding a serialized nvlist. .Fa nbytes should be set to the length in bytes of the serialized nvlist. .Fa buf should be pointed to a buffer storing the serialized nvlist. Userspace-backed PCM audio device nodes should be listed inside the serialized nvlist. .It Dv SNDSTIOC_FLUSH_USER_DEVS Flush any PCM audio devices previously added by callers. This ioctl takes no arguments. .El .Sh FILES .Bl -tag -width ".Pa /dev/sndstat" -compact .It Pa /dev/sndstat .El .Sh EXAMPLES The following code enumerates all available PCM audio devices: .Bd -literal -offset indent #include #include #include #include #include #include #include #include #include int main() { int fd; struct sndstioc_nv_arg arg; const nvlist_t * const *di; size_t i, nitems; nvlist_t *nvl; /* Open sndstat node in read-only first */ fd = open("/dev/sndstat", O_RDONLY); if (ioctl(fd, SNDSTIOC_REFRESH_DEVS, NULL)) err(1, "ioctl(fd, SNDSTIOC_REFRESH_DEVS, NULL)"); /* Get the size of snapshot, when nbytes = 0 */ arg.nbytes = 0; arg.buf = NULL; if (ioctl(fd, SNDSTIOC_GET_DEVS, &arg)) err(1, "ioctl(fd, SNDSTIOC_GET_DEVS, &arg)"); /* Get snapshot data */ arg.buf = malloc(arg.nbytes); if (arg.buf == NULL) err(EX_OSERR, "malloc"); if (ioctl(fd, SNDSTIOC_GET_DEVS, &arg)) err(1, "ioctl(fd, SNDSTIOC_GET_DEVS, &arg)"); /* Deserialize the nvlist stream */ nvl = nvlist_unpack(arg.buf, arg.nbytes, 0); free(arg.buf); /* Get DSPs array */ di = nvlist_get_nvlist_array(nvl, SNDST_DSPS, &nitems); for (i = 0; i < nitems; i++) { const char *nameunit, *devnode, *desc; /* * Examine each device nvlist item */ nameunit = nvlist_get_string(di[i], SNDST_DSPS_NAMEUNIT); devnode = nvlist_get_string(di[i], SNDST_DSPS_DEVNODE); desc = nvlist_get_string(di[i], SNDST_DSPS_DESC); printf("Name unit: `%s`, Device node: `%s`, Description: `%s`\n", nameunit, devnode, desc); } nvlist_destroy(nvl); return (0); } .Ed .Sh SEE ALSO .Xr sound 4 , .Xr nv 9 .Sh HISTORY The nvlist-based ioctls support for .Nm device first appeared in .Fx 13.0 . .Sh AUTHORS This manual page was written by .An Ka Ho Ng Aq Mt khng@FreeBSD.org .