Remove blank lines.
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mycroft
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@ -1,4 +1,4 @@
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.\" $NetBSD: audio.9,v 1.9 1999/03/16 00:40:47 garbled Exp $
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.\" $NetBSD: audio.9,v 1.10 1999/03/24 06:46:30 mycroft Exp $
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.\"
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.\" Copyright (c) 1996 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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@ -95,9 +95,8 @@ struct audio_params {
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void (*sw_code)__P((void *, u_char *, int));
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int factor; /* coding space change */
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};
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.Ed
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.Pp
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The high level audio driver attaches to the low level driver
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when the latter calls
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.Va audio_attach_mi .
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@ -110,7 +109,7 @@ This call should be
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void *hdl;
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struct device *dev;
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.Ed
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.Pp
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The
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.Va audio_hw_if
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struct is as shown above and the
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@ -124,7 +123,6 @@ in
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when the high level driver calls them.
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.Va dev
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is the device struct for the hardware device.
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.Pp
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The upper layer of the audio driver allocates one buffer for playing
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and one for recording. It handles the buffering of data from the
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@ -134,14 +132,12 @@ no data available from the user process when the hardware request
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another block a block of silence will be used instead. Furthermore,
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if the user process does not read data quickly enough during recording
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data will be thrown away.
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.Pp
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The fields of
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.Va audio_hw_if
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are described in some more detail below.
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Some fields are optional and can be set to 0 if not needed.
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.Bl -tag -width indent -compact
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.Bl -tag -width indent
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.It Dv int open(void *hdl, int flags)
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is called when the audio device is opened. It should initialize
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the hardware for I/O. Every successful call to
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@ -149,10 +145,8 @@ the hardware for I/O. Every successful call to
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is matched by a call to
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.Va close .
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Return 0 on success, otherwise an error code.
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.It Dv void close(void *hdl)
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is called when the audio device is closed.
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.It Dv int drain(void *hdl)
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optional, is called before the device is closed or when
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.Dv AUDIO_DRAIN
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@ -161,7 +155,6 @@ in to be played that could be lost when
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.Va close
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is called.
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Return 0 on success, otherwise an error code.
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.It Dv int query_encoding(void *hdl, struct audio_encoding *ae)
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is used when
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.Dv AUDIO_GETENC
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@ -169,7 +162,6 @@ is called. It should fill the
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.Va audio_encoding
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structure and return 0 or, if there is no encoding with the
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given number, return EINVAL.
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.It Dv int set_params(void *hdl, int setmode, int usemode,
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.Dv "struct audio_params *play, struct audio_params *rec)"
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.br
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@ -214,14 +206,12 @@ is copied into
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after the call to
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.Va set_params .
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Return 0 on success, otherwise an error code.
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.It Dv int round_blocksize(void *hdl, int bs)
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optional, is called with the block size,
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.Va bs ,
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that has been computed by the upper layer. It should return
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a block size, possibly changed according to the needs of the
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hardware driver.
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.It Dv int commit_settings(void *hdl)
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optional, is called after all calls to
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.Va set_params ,
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@ -231,7 +221,6 @@ are done. A hardware driver that needs to get the hardware in
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and out of command mode for each change can save all the changes
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during previous calls and do them all here.
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Return 0 on success, otherwise an error code.
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.It Dv int init_output(void *hdl, void *buffer, int size)
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optional, is called before any output starts, but when the total
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.Va size
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@ -240,7 +229,6 @@ of the output
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has been determined. It can be used to initialize looping DMA
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for hardware that needs that.
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Return 0 on success, otherwise an error code.
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.It Dv int init_input(void *hdl, void *buffer, int size)
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optional, is called before any input starts, but when the total
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.Va size
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@ -249,7 +237,6 @@ of the input
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has been determined. It can be used to initialize looping DMA
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for hardware that needs that.
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Return 0 on success, otherwise an error code.
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.It Dv int start_output(void *hdl, void *block, int bsize,
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.Dv "void (*intr)(void*), void *intrarg)"
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.br
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@ -268,7 +255,6 @@ Calling
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will normally initiate another call to
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.Va start_output .
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Return 0 on success, otherwise an error code.
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.It Dv int start_input(void *hdl, void *block, int bsize,
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.Dv "void (*intr)(void*), void *intrarg)"
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.br
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@ -287,37 +273,31 @@ Calling
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will normally initiate another call to
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.Va start_input.
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Return 0 on success, otherwise an error code.
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.It Dv int halt_output(void *hdl)
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is called to abort the output transfer (started by
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.Va start_output )
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in progress.
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Return 0 on success, otherwise an error code.
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.It Dv int halt_input(void *hdl)
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is called to abort the input transfer (started by
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.Va start_input )
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in progress.
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Return 0 on success, otherwise an error code.
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.It Dv int speaker_ctl(void *hdl, int on)
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optional, is called when a half duplex device changes between
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playing and recording. It can, e.g., be used to turn on
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and off the speaker.
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Return 0 on success, otherwise an error code.
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.It Dv int getdev(void *hdl, struct audio_device *ret)
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Should fill the
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.Va audio_device
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struct with relevant information about the driver.
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Return 0 on success, otherwise an error code.
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.It Dv int setfd(void *hdl, int fd)
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optional, is called when
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.Dv AUDIO_SETFD
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is used, but only if the device has AUDIO_PROP_FULLDUPLEX set.
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Return 0 on success, otherwise an error code.
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.It Dv int set_port(void *hdl, mixer_ctl_t *mc)
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is called in when
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.Dv AUDIO_MIXER_WRITE
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@ -325,7 +305,6 @@ is used. It should take data from the
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.Va mixer_ctl_t
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struct at set the corresponding mixer values.
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Return 0 on success, otherwise an error code.
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.It Dv int get_port(void *hdl, mixer_ctl_t *mc)
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is called in when
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.Dv AUDIO_MIXER_READ
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@ -333,7 +312,6 @@ is used. It should fill the
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.Va mixer_ctl_t
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struct.
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Return 0 on success, otherwise an error code.
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.It Dv int query_devinfo(void *hdl, mixer_devinfo_t *di)
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is called in when
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.Dv AUDIO_MIXER_DEVINFO
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@ -341,7 +319,6 @@ is used. It should fill the
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.Va mixer_devinfo_t
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struct.
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Return 0 on success, otherwise an error code.
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.It Dv "void *alloc(void *hdl, u_long size, int type, int flags)"
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.br
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optional, is called to allocate the device buffers. If not present
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@ -351,14 +328,12 @@ The reason for using a device dependent routine instead of
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.Xr malloc 9
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is that some buses need special allocation to do DMA.
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Returns the address of the buffer, or 0 on failure.
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.It Dv void free(void *hdl, void *addr, int type)
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optional, is called to free memory allocated by
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.Va alloc .
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If not supplied
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.Xr free 9
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is used.
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.It Dv u_long round_buffer(void *hdl, u_long bufsize)
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optional, is called at startup to determine the audio
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buffer size. The upper layer supplies the suggested
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@ -366,7 +341,6 @@ size in
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.Va bufsize ,
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which the hardware driver can then change if needed.
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E.g., DMA on the ISA bus cannot exceed 65536 bytes.
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.It Dv "int mappage(void *hdl, void *addr, int offs, int prot)"
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.br
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optional, is called for
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@ -379,12 +353,11 @@ mapped with protection
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.Va prot .
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Returns -1 on failure, or a machine dependent opaque value
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on success.
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.It Dv int get_props(void *hdl)
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Should return the device properties; i.e. a combination of
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AUDIO_PROP_xxx.
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.El
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.Pp
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The
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.Va query_devinfo
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method should define certain mixer controls for
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