[src/trunk]: src/share/man/man9 Improve wording, add more formatting.

[wiz <wiz%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/ab42846cc43c
branches:  trunk
changeset: 451193:ab42846cc43c
user:      wiz <wiz%NetBSD.org@localhost>
date:      Thu May 09 09:32:26 2019 +0000

description:
Improve wording, add more formatting.

diffstat:

 share/man/man9/audio.9 |  116 ++++++++++++++++++++++++++++--------------------
 1 files changed, 68 insertions(+), 48 deletions(-)

diffs (truncated from 314 to 300 lines):

diff -r a2a1ef68dd68 -r ab42846cc43c share/man/man9/audio.9
--- a/share/man/man9/audio.9    Thu May 09 09:22:13 2019 +0000
+++ b/share/man/man9/audio.9    Thu May 09 09:32:26 2019 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: audio.9,v 1.52 2019/05/08 14:25:39 isaki Exp $
+.\"    $NetBSD: audio.9,v 1.53 2019/05/09 09:32:26 wiz Exp $
 .\"
 .\" Copyright (c) 1999, 2000 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -147,7 +147,7 @@
 optional, is called when the first device combining playback and recording
 is opened.
 On a full duplex hardware,
-.Dv (FREAD | FWRITE)
+.Dv ( FREAD | FWRITE )
 is passed to flags.
 On a half duplex hardware,
 .Dv FWRITE
@@ -159,16 +159,19 @@
 is matched by a call to
 .Va close .
 Return 0 on success, otherwise an error code.
-It is called at Closed phase.
+It is called in the Closed phase.
 .It Dv void close(void *hdl)
 optional, is called when the last audio device combining
 playback and recording is closed.
-It is called at Opened phase.
+It is called in the Opened phase.
 .It Dv int query_format(void *hdl, audio_format_query_t *afp)
 is called to enumerate formats supported by the hardware.
-It should fill the audio_format_t structure according to given number
-afp->index.
-If there is no format with given number, return EINVAL.
+It should fill the
+.Vt audio_format_t
+structure according to given number
+.Va afp->index .
+If there is no format with given number, return
+.Er EINVAL .
 It is called at any time.
 .Bd -literal
 typedef struct audio_format_query {
@@ -179,26 +182,41 @@
 .Pp
 It is also used to determine the default format.
 The upper layer chooses the most preferred one as default format by following:
-.\" XXX I don't know syntax to represent <OL> in html
-1. Higher priority is preferred (normally 0, the highest is 3, the lowest is 0).
-2. AUDIO_ENCODING_SLINEAR_NE:16 is preferred if exists.
-3. AUDIO_ENCODING_SLINEAR_OE:16 is preferred if exists.
-4. More channels is preferred.
+.Bl -enum
+.It
+Higher priority is preferred (normally 0, the highest is 3, the lowest is 0).
+.It
+.Dv AUDIO_ENCODING_SLINEAR_NE:16
+is preferred if exists.
+.It
+.Dv AUDIO_ENCODING_SLINEAR_OE:16
+is preferred if exists.
+.It
+More channels is preferred.
+.El
 .Pp
-If the driver supports SLINEAR_NE:16 and the upper layer chooses it,
+If the driver supports
+.Dv SLINEAR_NE:16
+and the upper layer chooses it,
 the driver does not need to provide conversion function in
 .Va set_format .
-Similarly, if the driver supports SLINEAR_OE:16 and the upper layer chooses it,
-the driver does not need to provide conversion function.
+Similarly, if the driver supports
+.Dv SLINEAR_OE:16
+and the upper layer chooses it,
+the driver does not need to provide a conversion function.
 Because the upper layer only supports conversion between
-SLINEAR_NE:16 and SLINEAR_OE:16 for convenience.
-If the upper layer chooses other format,
-the driver needs to provide conversion function in
+.Dv SLINEAR_NE:16
+and
+.Dv SLINEAR_OE:16
+for convenience.
+If the upper layer chooses another format,
+the driver needs to provide a conversion function in
 .Va set_format .
 See also
 .Va set_format .
-If the driver can not provide the conversion from/to SLINEAR_NE:16,
-set priority to -1.
+If the driver can not provide the conversion from/to
+.Dv SLINEAR_NE:16 ,
+set priority to \-1.
 It means that the hardware supports this format but the driver does not
 (e.g. AC3), and it will never be chosen.
 .It Dv int set_foramt(void *hdl, int setmode,
@@ -239,7 +257,9 @@
 for playing or
 .Va rfil
 for recording.
-The definition of audio_filter_reg_t and related structure follow:
+The definition of
+.Vt audio_filter_reg_t
+and a related structure follow:
 .Bd -literal
 typedef struct {
        const void *src;
@@ -259,9 +279,9 @@
 .Ed
 .Pp
 .Va codec
-is conversion function and
+is a conversion function and
 .Va context
-is optional opaque pointer passed to
+is an optional opaque pointer passed to
 .Va codec .
 .Pp
 When
@@ -271,13 +291,13 @@
 are contained in
 .Va arg .
 .Va src
-points input buffer block,
+points to the input buffer block,
 .Va srcfmt
-contains input encoding parameter,
+contains the input encoding parameters,
 .Va dst
-points output buffer block and
+points to the output buffer block and
 .Va dstfmt
-contains output encoding parameter.
+contains the output encoding parameters.
 .Va count
 represents the number of frames to process on this call.
 .Va src
@@ -310,7 +330,7 @@
 and
 .Va rec .
 Return 0 on success, otherwise an error code.
-It is called at Attach or Closed phase.
+It is called in the Attach or Closed phases.
 .It Dv int round_blocksize(void *hdl, int bs, int mode,
 .Dv "const audio_params_t *param)"
 .Pp
@@ -326,7 +346,7 @@
 encoding parameters for the hardware.
 It should return a block size, possibly changed according to the needs
 of the hardware driver.
-It is called at Attach or Closed phase.
+It is called in the Attach or Closed phases.
 .It Dv int commit_settings(void *hdl)
 optional, is called after all calls to
 .Va set_params ,
@@ -337,7 +357,7 @@
 mode for each change can save all the changes during previous calls and
 do them all here.
 Return 0 on success, otherwise an error code.
-It is called at Attach or Closed phase.
+It is called in the Attach or Closed phases.
 .It Dv int init_output(void *hdl, void *buffer, int size)
 optional, is called before any output starts, but when the total
 .Va size
@@ -346,7 +366,7 @@
 has been determined.
 It can be used to initialize looping DMA for hardware that needs that.
 Return 0 on success, otherwise an error code.
-It is called at Attach or Closed phase.
+It is called in the Attach or Closed phases.
 .It Dv int init_input(void *hdl, void *buffer, int size)
 optional, is called before any input starts, but when the total
 .Va size
@@ -355,7 +375,7 @@
 has been determined.
 It can be used to initialize looping DMA for hardware that needs that.
 Return 0 on success, otherwise an error code.
-It is called at Attach or Closed phase.
+It is called in the Attach or Closed phases.
 .It Dv int start_output(void *hdl, void *block, int blksize,
 .Dv "void (*intr)(void*), void *intrarg)"
 .Pp
@@ -375,7 +395,7 @@
 will normally initiate another call to
 .Va start_output .
 Return 0 on success, otherwise an error code.
-It is called at Opened phase.
+It is called in the Opened phase.
 .It Dv int start_input(void *hdl, void *block, int blksize,
 .Dv "void (*intr)(void*), void *intrarg)"
 .Pp
@@ -395,32 +415,32 @@
 will normally initiate another call to
 .Va start_input .
 Return 0 on success, otherwise an error code.
-It is called at Opened phase.
+It is called in the Opened phase.
 .It Dv int halt_output(void *hdl)
 is called to abort the output transfer (started by
 .Va start_output )
 in progress.
 Return 0 on success, otherwise an error code.
-It is called at Opened phase.
+It is called in the Opened phase.
 .It Dv int halt_input(void *hdl)
 is called to abort the input transfer (started by
 .Va start_input )
 in progress.
 Return 0 on success, otherwise an error code.
-It is called at Opened phase.
+It is called in the Opened phase.
 .It Dv int speaker_ctl(void *hdl, int on)
 optional, is called when a half duplex device changes between
 playing and recording.
 It can, e.g., be used to turn on
 and off the speaker.
 Return 0 on success, otherwise an error code.
-It is called at Opened phase.
+It is called in the Opened phase.
 .It Dv int getdev(void *hdl, struct audio_device *ret)
 Should fill the
 .Va audio_device
 struct with relevant information about the driver.
 Return 0 on success, otherwise an error code.
-It is called at Opened phase.
+It is called in the Opened phase.
 .It Dv int set_port(void *hdl, mixer_ctrl_t *mc)
 is called in when
 .Dv AUDIO_MIXER_WRITE
@@ -429,7 +449,7 @@
 .Va mixer_ctrl_t
 struct at set the corresponding mixer values.
 Return 0 on success, otherwise an error code.
-It is called at Opened or Closed phase.
+It is called in the Opened or Closed phases.
 .It Dv int get_port(void *hdl, mixer_ctrl_t *mc)
 is called in when
 .Dv AUDIO_MIXER_READ
@@ -438,7 +458,7 @@
 .Va mixer_ctrl_t
 struct.
 Return 0 on success, otherwise an error code.
-It is called at Opened or Closed phase.
+It is called in the Opened or Closed phases.
 .It Dv int query_devinfo(void *hdl, mixer_devinfo_t *di)
 is called in when
 .Dv AUDIO_MIXER_DEVINFO
@@ -459,14 +479,14 @@
 Returns the address of the buffer, or
 .Dv NULL
 on failure.
-It is called at Attached or Closed phase.
+It is called in the Attached or Closed phases.
 .It Dv void freem(void *hdl, void *addr, size_t size)
 optional, is called to free memory allocated by
 .Va allocm .
 If not supplied
 .Xr free 9
 is used.
-It is called at Attached or Closed phase.
+It is called in the Attached or Closed phases.
 .It Dv size_t round_buffersize(void *hdl, int direction, size_t bufsize)
 optional, is called at startup to determine the audio
 buffer size.
@@ -474,14 +494,14 @@
 .Va bufsize ,
 which the hardware driver can then change if needed.
 E.g., DMA on the ISA bus cannot exceed 65536 bytes.
-It is called at Attached or Closed phase.
+It is called in the Attached or Closed phases.
 .It Dv int get_props(void *hdl)
 Should return the device properties; i.e., a combination of
 AUDIO_PROP_xxx.
 It is called at any time.
 .Pp
 .Dv AUDIO_PROP_MMAP
-is acceptable but obsoleted, so new drivers should not return this property.
+is acceptable but obsolete, so new drivers should not return this property.
 .It Dv int trigger_output(void *hdl, void *start, void *end,
 .Dv "int blksize, void (*intr)(void*), void *intrarg,"
 .Pp
@@ -506,7 +526,7 @@
 Once started the transfer may be stopped using
 .Va halt_output .
 Return 0 on success, otherwise an error code.
-It is called at Opened phase.
+It is called in the Opened phase.
 .It Dv int trigger_input(void *hdl, void *start, void *end,
 .Dv "int blksize, void (*intr)(void*), void *intrarg,"
 .Pp
@@ -531,7 +551,7 @@
 Once started the transfer may be stopped using
 .Va halt_input .
 Return 0 on success, otherwise an error code.
-It is called at Opened phase.
+It is called in the Opened phase.
 .It Dv int dev_ioctl(void *hdl, u_long cmd, void *addr,
 .Pp