mirror of
https://github.com/freebsd/freebsd-src
synced 2024-07-21 18:27:22 +00:00
pcm.4: Fix lint warnings
Ignore the "manual not found" warnings for snd_ai2s(4) and snd_davbus(4). Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Reviewed by: markj Differential Revision: https://reviews.freebsd.org/D43996
This commit is contained in:
Christos Margiolis
parent
a9341f0f0a
commit
8bfb23abf8
|
|
@ -167,16 +167,16 @@ This will mute the input channel per default.
|
|||
Multichannel audio, popularly referred to as
|
||||
.Dq surround sound
|
||||
is supported and enabled by default.
|
||||
The FreeBSD 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
|
||||
.Fx
|
||||
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
|
||||
.Fn ioctl
|
||||
support.
|
||||
Multichannel audio works both with and without
|
||||
.Tn VCHANs .
|
||||
Multichannel audio works both with and without VCHANs.
|
||||
.Pp
|
||||
Most bridge device drivers are still missing multichannel matrixing
|
||||
support, but in most cases this should be trivial to implement.
|
||||
|
|
@ -202,21 +202,18 @@ tunable.
|
|||
Each device can optionally support more playback and recording channels
|
||||
than physical hardware provides by using
|
||||
.Dq virtual channels
|
||||
or
|
||||
.Tn VCHANs .
|
||||
.Tn VCHAN
|
||||
options can be configured via the
|
||||
or VCHANs.
|
||||
VCHAN options can be configured via the
|
||||
.Xr sysctl 8
|
||||
interface but can only be manipulated while the device is inactive.
|
||||
.Ss VPC
|
||||
FreeBSD supports independent and individual volume controls for each active
|
||||
.Fx
|
||||
supports independent and individual volume controls for each active
|
||||
application, without touching the master
|
||||
.Nm
|
||||
volume.
|
||||
This is sometimes referred to as Volume Per Channel (VPC).
|
||||
The
|
||||
.Tn VPC
|
||||
feature is enabled by default.
|
||||
The VPC feature is enabled by default.
|
||||
.Ss Loader Tunables
|
||||
The following loader tunables are used to set driver configuration at the
|
||||
.Xr loader 8
|
||||
|
|
@ -238,12 +235,9 @@ Enabling this will make bass and treble controls appear in mixer applications.
|
|||
This tunable is undefined by default.
|
||||
Equalizing is disabled by default.
|
||||
.It Va hint.pcm.%d.vpc
|
||||
Set to 1 or 0 to explicitly enable (1) or disable (0) the
|
||||
.Tn VPC
|
||||
feature.
|
||||
Set to 1 or 0 to explicitly enable (1) or disable (0) the VPC feature.
|
||||
This tunable is undefined by default.
|
||||
.Tn VPC
|
||||
is however enabled by default.
|
||||
VPC is however enabled by default.
|
||||
.El
|
||||
.Ss Runtime Configuration
|
||||
There are a number of
|
||||
|
|
@ -365,16 +359,12 @@ 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.
|
||||
.It Va hw.snd.maxautovchans
|
||||
Global
|
||||
.Tn VCHAN
|
||||
setting that only affects devices with at least one playback or recording channel available.
|
||||
The sound system will dynamically create up to this many
|
||||
.Tn VCHANs .
|
||||
Global VCHAN setting that only affects devices with at least one playback or
|
||||
recording channel available.
|
||||
The sound system will dynamically create up to this many VCHANs.
|
||||
Set to
|
||||
.Dq 0
|
||||
if no
|
||||
.Tn VCHANs
|
||||
are desired.
|
||||
if no VCHANs are desired.
|
||||
Maximum value is 256.
|
||||
.It Va hw.snd.report_soft_formats
|
||||
Controls the internal format conversion if it is
|
||||
|
|
@ -419,13 +409,11 @@ 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.
|
||||
.It Va hw.snd.vpc_mixer_bypass
|
||||
The recommended way to use the
|
||||
.Tn VPC
|
||||
feature is to teach applications to use
|
||||
the correct
|
||||
The recommended way to use the VPC feature is to teach applications to use the
|
||||
correct
|
||||
.Fn ioctl :
|
||||
.Dv SNDCTL_DSP_GETPLAYVOL, SNDCTL_DSP_SETPLAYVOL,
|
||||
.Dv SNDCTL_DSP_SETRECVOL, SNDCTL_DSP_SETRECVOL.
|
||||
.Dv SNDCTL_DSP_GETPLAYVOL , SNDCTL_DSP_SETPLAYVOL ,
|
||||
.Dv SNDCTL_DSP_SETRECVOL , SNDCTL_DSP_SETRECVOL .
|
||||
This is however not always possible.
|
||||
Enable this to allow applications to use their own existing mixer logic
|
||||
to control their own channel volume.
|
||||
|
|
@ -438,30 +426,19 @@ matrixing, rate converting and equalizing.
|
|||
The pure
|
||||
.Nm
|
||||
stream will be fed directly to the hardware.
|
||||
If
|
||||
.Tn VCHANs
|
||||
are enabled, the bitperfect mode will use the
|
||||
.Tn VCHAN
|
||||
format/rate as the definitive format/rate target.
|
||||
The recommended way to use bitperfect mode is to disable
|
||||
.Tn VCHANs
|
||||
and enable this sysctl.
|
||||
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.
|
||||
.It Va dev.pcm.%d.[play|rec].vchans
|
||||
The current number of
|
||||
.Tn VCHANs
|
||||
allocated per device.
|
||||
This can be set to preallocate a certain number of
|
||||
.Tn VCHANs .
|
||||
The current number of VCHANs allocated per device.
|
||||
This can be set to preallocate a certain number of VCHANs.
|
||||
Setting this value to
|
||||
.Dq 0
|
||||
will disable
|
||||
.Tn VCHANs
|
||||
for this device.
|
||||
will disable VCHANs for this device.
|
||||
.It Va dev.pcm.%d.[play|rec].vchanformat
|
||||
Format for
|
||||
.Tn VCHAN
|
||||
mixing.
|
||||
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.
|
||||
|
|
@ -491,8 +468,7 @@ Quadraphonic, 4 channels (front/rear left and right).
|
|||
8 channels (4.0 + center + LFE + left and right side).
|
||||
.El
|
||||
.It Va dev.pcm.%d.[play|rec].vchanmode
|
||||
.Tn VCHAN
|
||||
format/rate selection.
|
||||
VCHAN format/rate selection.
|
||||
Available options include:
|
||||
.Bl -tag -width 2n
|
||||
.It fixed
|
||||
|
|
@ -527,9 +503,7 @@ The downside is that the hardware DMA mode needs to be restarted, which may
|
|||
cause annoying pops or clicks.
|
||||
.El
|
||||
.It Va dev.pcm.%d.[play|rec].vchanrate
|
||||
Sample rate speed for
|
||||
.Tn VCHAN
|
||||
mixing.
|
||||
Sample rate speed for VCHAN mixing.
|
||||
All playback paths will be converted to this sample rate before the mixing
|
||||
process begins.
|
||||
.It Va dev.pcm.%d.polling
|
||||
|
|
@ -552,17 +526,12 @@ 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.
|
||||
.Ss IOCTL Support
|
||||
The driver supports most of the
|
||||
.Tn OSS
|
||||
The driver supports most of the OSS
|
||||
.Fn ioctl
|
||||
functions, and most applications work unmodified.
|
||||
A few differences exist, while memory mapped playback is
|
||||
supported natively and in
|
||||
.Tn Linux
|
||||
emulation, memory mapped recording is
|
||||
not due to
|
||||
.Tn VM
|
||||
system design.
|
||||
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
|
||||
|
|
|
|||
Loading…
Reference in a new issue