€•@Z      Œsphinx.addnodes”Œdocument”“”)”}”(Œ	rawsource”Œ ”Œchildren”]”(Œtranslations”ŒLanguagesNode”“”)”}”(hhh]”(h Œpending_xref”“”)”}”(hhh]”Œdocutils.nodes”ŒText”“”ŒChinese (Simplified)”…””}”Œparent”hsbaŒ
attributes”}”(Œids”]”Œclasses”]”Œnames”]”Œdupnames”]”Œbackrefs”]”Œ	refdomain”Œstd”Œreftype”Œdoc”Œ	reftarget”Œ5/translations/zh_CN/sound/designs/channel-mapping-api”Œmodname”NŒ	classname”NŒrefexplicit”ˆuŒtagname”hhhubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ5/translations/zh_TW/sound/designs/channel-mapping-api”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ5/translations/it_IT/sound/designs/channel-mapping-api”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ5/translations/ja_JP/sound/designs/channel-mapping-api”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ5/translations/ko_KR/sound/designs/channel-mapping-api”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ5/translations/sp_SP/sound/designs/channel-mapping-api”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h
hhŒ	_document”hŒsource”NŒline”NubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒALSA PCM channel-mapping API”h]”hŒALSA PCM channel-mapping API”…””}”(hh¨hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hh£hžhhŸŒO/var/lib/git/docbuild/linux/Documentation/sound/designs/channel-mapping-api.rst”h KubhŒ	paragraph”“”)”}”(hŒTakashi Iwai <tiwai@suse.de>”h]”(hŒTakashi Iwai <”…””}”(hh¹hžhhŸNh NubhŒ	reference”“”)”}”(hŒtiwai@suse.de”h]”hŒtiwai@suse.de”…””}”(hhÃhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”Œrefuri”Œmailto:tiwai@suse.de”uh1hÁhh¹ubhŒ>”…””}”(hh¹hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khh£hžhubh¢)”}”(hhh]”(h§)”}”(hŒGeneral”h]”hŒGeneral”…””}”(hhàhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hhÝhžhhŸh¶h Kubh¸)”}”(hŒ¤The channel mapping API allows user to query the possible channel maps
and the current channel map, also optionally to modify the channel map
of the current stream.”h]”hŒ¤The channel mapping API allows user to query the possible channel maps
and the current channel map, also optionally to modify the channel map
of the current stream.”…””}”(hhîhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K
hhÝhžhubh¸)”}”(hŒüA channel map is an array of position for each PCM channel.
Typically, a stereo PCM stream has a channel map of
``{ front_left, front_right }``
while a 4.0 surround PCM stream has a channel map of
``{ front left, front right, rear left, rear right }.``”h]”(hŒpA channel map is an array of position for each PCM channel.
Typically, a stereo PCM stream has a channel map of
”…””}”(hhühžhhŸNh NubhŒliteral”“”)”}”(hŒ``{ front_left, front_right }``”h]”hŒ{ front_left, front_right }”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hhüubhŒ6
while a 4.0 surround PCM stream has a channel map of
”…””}”(hhühžhhŸNh Nubj  )”}”(hŒ7``{ front left, front right, rear left, rear right }.``”h]”hŒ3{ front left, front right, rear left, rear right }.”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hhüubeh}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KhhÝhžhubh¸)”}”(hXŠ  The problem, so far, was that we had no standard channel map
explicitly, and applications had no way to know which channel
corresponds to which (speaker) position.  Thus, applications applied
wrong channels for 5.1 outputs, and you hear suddenly strange sound
from rear.  Or, some devices secretly assume that center/LFE is the
third/fourth channels while others that C/LFE as 5th/6th channels.”h]”hXŠ  The problem, so far, was that we had no standard channel map
explicitly, and applications had no way to know which channel
corresponds to which (speaker) position.  Thus, applications applied
wrong channels for 5.1 outputs, and you hear suddenly strange sound
from rear.  Or, some devices secretly assume that center/LFE is the
third/fourth channels while others that C/LFE as 5th/6th channels.”…””}”(hj,  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KhhÝhžhubh¸)”}”(hX  Also, some devices such as HDMI are configurable for different speaker
positions even with the same number of total channels.  However, there
was no way to specify this because of lack of channel map
specification.  These are the main motivations for the new channel
mapping API.”h]”hX  Also, some devices such as HDMI are configurable for different speaker
positions even with the same number of total channels.  However, there
was no way to specify this because of lack of channel map
specification.  These are the main motivations for the new channel
mapping API.”…””}”(hj:  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KhhÝhžhubeh}”(h]”Œgeneral”ah ]”h"]”Œgeneral”ah$]”h&]”uh1h¡hh£hžhhŸh¶h Kubh¢)”}”(hhh]”(h§)”}”(hŒDesign”h]”hŒDesign”…””}”(hjS  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjP  hžhhŸh¶h K#ubh¸)”}”(hŒ¡Actually, "the channel mapping API" doesn't introduce anything new in
the kernel/user-space ABI perspective.  It uses only the existing
control element features.”h]”hŒ§Actually, â€œthe channel mapping APIâ€ doesnâ€™t introduce anything new in
the kernel/user-space ABI perspective.  It uses only the existing
control element features.”…””}”(hja  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K%hjP  hžhubh¸)”}”(hŒ As a ground design, each PCM substream may contain a control element
providing the channel mapping information and configuration.  This
element is specified by:”h]”hŒ As a ground design, each PCM substream may contain a control element
providing the channel mapping information and configuration.  This
element is specified by:”…””}”(hjo  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K)hjP  hžhubhŒbullet_list”“”)”}”(hhh]”(hŒ	list_item”“”)”}”(hŒ iface = SNDRV_CTL_ELEM_IFACE_PCM”h]”h¸)”}”(hj†  h]”hŒ iface = SNDRV_CTL_ELEM_IFACE_PCM”…””}”(hjˆ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K-hj„  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j‚  hj  hžhhŸh¶h Nubjƒ  )”}”(hŒ6name = "Playback Channel Map" or "Capture Channel Map"”h]”h¸)”}”(hj  h]”hŒ>name = â€œPlayback Channel Mapâ€ or â€œCapture Channel Mapâ€”…””}”(hjŸ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K.hj›  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j‚  hj  hžhhŸh¶h Nubjƒ  )”}”(hŒ>device = the same device number for the assigned PCM substream”h]”h¸)”}”(hj´  h]”hŒ>device = the same device number for the assigned PCM substream”…””}”(hj¶  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K/hj²  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j‚  hj  hžhhŸh¶h Nubjƒ  )”}”(hŒ=index = the same index number for the assigned PCM substream
”h]”h¸)”}”(hŒ<index = the same index number for the assigned PCM substream”h]”hŒ<index = the same index number for the assigned PCM substream”…””}”(hjÍ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K0hjÉ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j‚  hj  hžhhŸh¶h Nubeh}”(h]”h ]”h"]”h$]”h&]”Œbullet”Œ*”uh1j}  hŸh¶h K-hjP  hžhubh¸)”}”(hŒDNote the name is different depending on the PCM substream direction.”h]”hŒDNote the name is different depending on the PCM substream direction.”…””}”(hjé  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K2hjP  hžhubh¸)”}”(hŒ»Each control element provides at least the TLV read operation and the
read operation.  Optionally, the write operation can be provided to
allow user to change the channel map dynamically.”h]”hŒ»Each control element provides at least the TLV read operation and the
read operation.  Optionally, the write operation can be provided to
allow user to change the channel map dynamically.”…””}”(hj÷  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K4hjP  hžhubh¢)”}”(hhh]”(h§)”}”(hŒTLV”h]”hŒTLV”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hj  hžhhŸh¶h K9ubh¸)”}”(hX4  The TLV operation gives the list of available channel
maps.  A list item of a channel map is usually a TLV of
``type data-bytes ch0 ch1 ch2...``
where type is the TLV type value, the second argument is the total
bytes (not the numbers) of channel values, and the rest are the
position value for each channel.”h]”(hŒnThe TLV operation gives the list of available channel
maps.  A list item of a channel map is usually a TLV of
”…””}”(hj  hžhhŸNh Nubj  )”}”(hŒ"``type data-bytes ch0 ch1 ch2...``”h]”hŒtype data-bytes ch0 ch1 ch2...”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hj  ubhŒ¤
where type is the TLV type value, the second argument is the total
bytes (not the numbers) of channel values, and the rest are the
position value for each channel.”…””}”(hj  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K;hj  hžhubh¸)”}”(hX:  As a TLV type, either ``SNDRV_CTL_TLVT_CHMAP_FIXED``,
``SNDRV_CTL_TLV_CHMAP_VAR`` or ``SNDRV_CTL_TLVT_CHMAP_PAIRED`` can be used.
The ``_FIXED`` type is for a channel map with the fixed channel position
while the latter two are for flexible channel positions. ``_VAR`` type is
for a channel map where all channels are freely swappable and ``_PAIRED``
type is where pair-wise channels are swappable.  For example, when you
have {FL/FR/RL/RR} channel map, ``_PAIRED`` type would allow you to swap
only {RL/RR/FL/FR} while ``_VAR`` type would allow even swapping FL and
RR.”h]”(hŒAs a TLV type, either ”…””}”(hj6  hžhhŸNh Nubj  )”}”(hŒ``SNDRV_CTL_TLVT_CHMAP_FIXED``”h]”hŒSNDRV_CTL_TLVT_CHMAP_FIXED”…””}”(hj>  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hj6  ubhŒ,
”…””}”(hj6  hžhhŸNh Nubj  )”}”(hŒ``SNDRV_CTL_TLV_CHMAP_VAR``”h]”hŒSNDRV_CTL_TLV_CHMAP_VAR”…””}”(hjP  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hj6  ubhŒ or ”…””}”(hj6  hžhhŸNh Nubj  )”}”(hŒ``SNDRV_CTL_TLVT_CHMAP_PAIRED``”h]”hŒSNDRV_CTL_TLVT_CHMAP_PAIRED”…””}”(hjb  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hj6  ubhŒ can be used.
The ”…””}”(hj6  hžhhŸNh Nubj  )”}”(hŒ
``_FIXED``”h]”hŒ_FIXED”…””}”(hjt  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hj6  ubhŒt type is for a channel map with the fixed channel position
while the latter two are for flexible channel positions. ”…””}”(hj6  hžhhŸNh Nubj  )”}”(hŒ``_VAR``”h]”hŒ_VAR”…””}”(hj†  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hj6  ubhŒG type is
for a channel map where all channels are freely swappable and ”…””}”(hj6  hžhhŸNh Nubj  )”}”(hŒ``_PAIRED``”h]”hŒ_PAIRED”…””}”(hj˜  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hj6  ubhŒh
type is where pair-wise channels are swappable.  For example, when you
have {FL/FR/RL/RR} channel map, ”…””}”(hj6  hžhhŸNh Nubj  )”}”(hŒ``_PAIRED``”h]”hŒ_PAIRED”…””}”(hjª  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hj6  ubhŒ7 type would allow you to swap
only {RL/RR/FL/FR} while ”…””}”(hj6  hžhhŸNh Nubj  )”}”(hŒ``_VAR``”h]”hŒ_VAR”…””}”(hj¼  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hj6  ubhŒ* type would allow even swapping FL and
RR.”…””}”(hj6  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KBhj  hžhubh¸)”}”(hŒ3These new TLV types are defined in ``sound/tlv.h``.”h]”(hŒ#These new TLV types are defined in ”…””}”(hjÔ  hžhhŸNh Nubj  )”}”(hŒ``sound/tlv.h``”h]”hŒsound/tlv.h”…””}”(hjÜ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hjÔ  ubhŒ.”…””}”(hjÔ  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KLhj  hžhubh¸)”}”(hŒWThe available channel position values are defined in ``sound/asound.h``,
here is a cut:”h]”(hŒ5The available channel position values are defined in ”…””}”(hjô  hžhhŸNh Nubj  )”}”(hŒ``sound/asound.h``”h]”hŒsound/asound.h”…””}”(hjü  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hjô  ubhŒ,
here is a cut:”…””}”(hjô  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KNhj  hžhubhŒliteral_block”“”)”}”(hX
  /* channel positions */
enum {
      SNDRV_CHMAP_UNKNOWN = 0,
      SNDRV_CHMAP_NA,         /* N/A, silent */
      SNDRV_CHMAP_MONO,       /* mono stream */
      /* this follows the alsa-lib mixer channel value + 3 */
      SNDRV_CHMAP_FL,         /* front left */
      SNDRV_CHMAP_FR,         /* front right */
      SNDRV_CHMAP_RL,         /* rear left */
      SNDRV_CHMAP_RR,         /* rear right */
      SNDRV_CHMAP_FC,         /* front center */
      SNDRV_CHMAP_LFE,        /* LFE */
      SNDRV_CHMAP_SL,         /* side left */
      SNDRV_CHMAP_SR,         /* side right */
      SNDRV_CHMAP_RC,         /* rear center */
      /* new definitions */
      SNDRV_CHMAP_FLC,        /* front left center */
      SNDRV_CHMAP_FRC,        /* front right center */
      SNDRV_CHMAP_RLC,        /* rear left center */
      SNDRV_CHMAP_RRC,        /* rear right center */
      SNDRV_CHMAP_FLW,        /* front left wide */
      SNDRV_CHMAP_FRW,        /* front right wide */
      SNDRV_CHMAP_FLH,        /* front left high */
      SNDRV_CHMAP_FCH,        /* front center high */
      SNDRV_CHMAP_FRH,        /* front right high */
      SNDRV_CHMAP_TC,         /* top center */
      SNDRV_CHMAP_TFL,        /* top front left */
      SNDRV_CHMAP_TFR,        /* top front right */
      SNDRV_CHMAP_TFC,        /* top front center */
      SNDRV_CHMAP_TRL,        /* top rear left */
      SNDRV_CHMAP_TRR,        /* top rear right */
      SNDRV_CHMAP_TRC,        /* top rear center */
      SNDRV_CHMAP_LAST = SNDRV_CHMAP_TRC,
};”h]”hX
  /* channel positions */
enum {
      SNDRV_CHMAP_UNKNOWN = 0,
      SNDRV_CHMAP_NA,         /* N/A, silent */
      SNDRV_CHMAP_MONO,       /* mono stream */
      /* this follows the alsa-lib mixer channel value + 3 */
      SNDRV_CHMAP_FL,         /* front left */
      SNDRV_CHMAP_FR,         /* front right */
      SNDRV_CHMAP_RL,         /* rear left */
      SNDRV_CHMAP_RR,         /* rear right */
      SNDRV_CHMAP_FC,         /* front center */
      SNDRV_CHMAP_LFE,        /* LFE */
      SNDRV_CHMAP_SL,         /* side left */
      SNDRV_CHMAP_SR,         /* side right */
      SNDRV_CHMAP_RC,         /* rear center */
      /* new definitions */
      SNDRV_CHMAP_FLC,        /* front left center */
      SNDRV_CHMAP_FRC,        /* front right center */
      SNDRV_CHMAP_RLC,        /* rear left center */
      SNDRV_CHMAP_RRC,        /* rear right center */
      SNDRV_CHMAP_FLW,        /* front left wide */
      SNDRV_CHMAP_FRW,        /* front right wide */
      SNDRV_CHMAP_FLH,        /* front left high */
      SNDRV_CHMAP_FCH,        /* front center high */
      SNDRV_CHMAP_FRH,        /* front right high */
      SNDRV_CHMAP_TC,         /* top center */
      SNDRV_CHMAP_TFL,        /* top front left */
      SNDRV_CHMAP_TFR,        /* top front right */
      SNDRV_CHMAP_TFC,        /* top front center */
      SNDRV_CHMAP_TRL,        /* top rear left */
      SNDRV_CHMAP_TRR,        /* top rear right */
      SNDRV_CHMAP_TRC,        /* top rear center */
      SNDRV_CHMAP_LAST = SNDRV_CHMAP_TRC,
};”…””}”hj  sbah}”(h]”h ]”h"]”h$]”h&]”Œ	xml:space”Œpreserve”uh1j  hŸh¶h KShj  hžhubh¸)”}”(hŒ­When a PCM stream can provide more than one channel map, you can
provide multiple channel maps in a TLV container type.  The TLV data
to be returned will contain such as:
::”h]”hŒªWhen a PCM stream can provide more than one channel map, you can
provide multiple channel maps in a TLV container type.  The TLV data
to be returned will contain such as:”…””}”(hj&  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Kvhj  hžhubj  )”}”(hŒñSNDRV_CTL_TLVT_CONTAINER 96
    SNDRV_CTL_TLVT_CHMAP_FIXED 4 SNDRV_CHMAP_FC
    SNDRV_CTL_TLVT_CHMAP_FIXED 8 SNDRV_CHMAP_FL SNDRV_CHMAP_FR
    SNDRV_CTL_TLVT_CHMAP_FIXED 16 NDRV_CHMAP_FL SNDRV_CHMAP_FR \
        SNDRV_CHMAP_RL SNDRV_CHMAP_RR”h]”hŒñSNDRV_CTL_TLVT_CONTAINER 96
    SNDRV_CTL_TLVT_CHMAP_FIXED 4 SNDRV_CHMAP_FC
    SNDRV_CTL_TLVT_CHMAP_FIXED 8 SNDRV_CHMAP_FL SNDRV_CHMAP_FR
    SNDRV_CTL_TLVT_CHMAP_FIXED 16 NDRV_CHMAP_FL SNDRV_CHMAP_FR \
        SNDRV_CHMAP_RL SNDRV_CHMAP_RR”…””}”hj4  sbah}”(h]”h ]”h"]”h$]”h&]”j$  j%  uh1j  hŸh¶h K{hj  hžhubh¸)”}”(hŒZThe channel position is provided in LSB 16bits.  The upper bits are
used for bit flags.
::”h]”hŒWThe channel position is provided in LSB 16bits.  The upper bits are
used for bit flags.”…””}”(hjB  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khj  hžhubj  )”}”(hŒ˜#define SNDRV_CHMAP_POSITION_MASK       0xffff
#define SNDRV_CHMAP_PHASE_INVERSE       (0x01 << 16)
#define SNDRV_CHMAP_DRIVER_SPEC         (0x02 << 16)”h]”hŒ˜#define SNDRV_CHMAP_POSITION_MASK       0xffff
#define SNDRV_CHMAP_PHASE_INVERSE       (0x01 << 16)
#define SNDRV_CHMAP_DRIVER_SPEC         (0x02 << 16)”…””}”hjP  sbah}”(h]”h ]”h"]”h$]”h&]”j$  j%  uh1j  hŸh¶h K…hj  hžhubh¸)”}”(hŒ±``SNDRV_CHMAP_PHASE_INVERSE`` indicates the channel is phase inverted,
(thus summing left and right channels would result in almost silence).
Some digital mic devices have this.”h]”(j  )”}”(hŒ``SNDRV_CHMAP_PHASE_INVERSE``”h]”hŒSNDRV_CHMAP_PHASE_INVERSE”…””}”(hjb  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hj^  ubhŒ” indicates the channel is phase inverted,
(thus summing left and right channels would result in almost silence).
Some digital mic devices have this.”…””}”(hj^  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K‰hj  hžhubh¸)”}”(hŒˆWhen ``SNDRV_CHMAP_DRIVER_SPEC`` is set, all the channel position values
don't follow the standard definition above but driver-specific.”h]”(hŒWhen ”…””}”(hjz  hžhhŸNh Nubj  )”}”(hŒ``SNDRV_CHMAP_DRIVER_SPEC``”h]”hŒSNDRV_CHMAP_DRIVER_SPEC”…””}”(hj‚  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hjz  ubhŒj is set, all the channel position values
donâ€™t follow the standard definition above but driver-specific.”…””}”(hjz  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khj  hžhubeh}”(h]”Œtlv”ah ]”h"]”Œtlv”ah$]”h&]”uh1h¡hjP  hžhhŸh¶h K9ubh¢)”}”(hhh]”(h§)”}”(hŒRead Operation”h]”hŒRead Operation”…””}”(hj¥  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hj¢  hžhhŸh¶h K‘ubh¸)”}”(hŒ¯The control read operation is for providing the current channel map of
the given stream.  The control element returns an integer array
containing the position of each channel.”h]”hŒ¯The control read operation is for providing the current channel map of
the given stream.  The control element returns an integer array
containing the position of each channel.”…””}”(hj³  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K“hj¢  hžhubh¸)”}”(hŒWhen this is performed before the number of the channel is specified
(i.e. hw_params is set), it should return all channels set to
``UNKNOWN``.”h]”(hŒƒWhen this is performed before the number of the channel is specified
(i.e. hw_params is set), it should return all channels set to
”…””}”(hjÁ  hžhhŸNh Nubj  )”}”(hŒ``UNKNOWN``”h]”hŒUNKNOWN”…””}”(hjÉ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hjÁ  ubhŒ.”…””}”(hjÁ  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K—hj¢  hžhubeh}”(h]”Œread-operation”ah ]”h"]”Œread operation”ah$]”h&]”uh1h¡hjP  hžhhŸh¶h K‘ubh¢)”}”(hhh]”(h§)”}”(hŒWrite Operation”h]”hŒWrite Operation”…””}”(hjì  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjé  hžhhŸh¶h Kœubh¸)”}”(hŒýThe control write operation is optional, and only for devices that can
change the channel configuration on the fly, such as HDMI.  User needs
to pass an integer value containing the valid channel positions for
all channels of the assigned PCM substream.”h]”hŒýThe control write operation is optional, and only for devices that can
change the channel configuration on the fly, such as HDMI.  User needs
to pass an integer value containing the valid channel positions for
all channels of the assigned PCM substream.”…””}”(hjú  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Kžhjé  hžhubh¸)”}”(hŒmThis operation is allowed only at PCM PREPARED state.  When called in
other states, it shall return an error.”h]”hŒmThis operation is allowed only at PCM PREPARED state.  When called in
other states, it shall return an error.”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K£hjé  hžhubeh}”(h]”Œwrite-operation”ah ]”h"]”Œwrite operation”ah$]”h&]”uh1h¡hjP  hžhhŸh¶h Kœubeh}”(h]”Œdesign”ah ]”h"]”Œdesign”ah$]”h&]”uh1h¡hh£hžhhŸh¶h K#ubeh}”(h]”Œalsa-pcm-channel-mapping-api”ah ]”h"]”Œalsa pcm channel-mapping api”ah$]”h&]”uh1h¡hhhžhhŸh¶h Kubeh}”(h]”h ]”h"]”h$]”h&]”Œsource”h¶uh1hŒcurrent_source”NŒcurrent_line”NŒsettings”Œdocutils.frontend”ŒValues”“”)”}”(h¦NŒ	generator”NŒ	datestamp”NŒsource_link”NŒ
source_url”NŒtoc_backlinks”Œentry”Œfootnote_backlinks”KŒsectnum_xform”KŒstrip_comments”NŒstrip_elements_with_classes”NŒstrip_classes”NŒreport_level”KŒ
halt_level”KŒexit_status_level”KŒdebug”NŒwarning_stream”NŒ	traceback”ˆŒinput_encoding”Œ	utf-8-sig”Œinput_encoding_error_handler”Œstrict”Œoutput_encoding”Œutf-8”Œoutput_encoding_error_handler”jQ  Œerror_encoding”Œutf-8”Œerror_encoding_error_handler”Œbackslashreplace”Œlanguage_code”Œen”Œrecord_dependencies”NŒconfig”NŒ	id_prefix”hŒauto_id_prefix”Œid”Œdump_settings”NŒdump_internals”NŒdump_transforms”NŒdump_pseudo_xml”NŒexpose_internals”NŒstrict_visitor”NŒ_disable_config”NŒ_source”h¶Œ_destination”NŒ_config_files”]”Œ7/var/lib/git/docbuild/linux/Documentation/docutils.conf”aŒfile_insertion_enabled”ˆŒraw_enabled”KŒline_length_limit”M'Œpep_references”NŒpep_base_url”Œhttps://peps.python.org/”Œpep_file_url_template”Œpep-%04d”Œrfc_references”NŒrfc_base_url”Œ&https://datatracker.ietf.org/doc/html/”Œ	tab_width”KŒtrim_footnote_reference_space”‰Œsyntax_highlight”Œlong”Œsmart_quotes”ˆŒsmartquotes_locales”]”Œcharacter_level_inline_markup”‰Œdoctitle_xform”‰Œdocinfo_xform”KŒsectsubtitle_xform”‰Œimage_loading”Œlink”Œembed_stylesheet”‰Œcloak_email_addresses”ˆŒsection_self_link”‰Œenv”NubŒreporter”NŒindirect_targets”]”Œsubstitution_defs”}”Œsubstitution_names”}”Œrefnames”}”Œrefids”}”Œnameids”}”(j+  j(  jM  jJ  j#  j   jŸ  jœ  jæ  jã  j  j  uŒ	nametypes”}”(j+  ‰jM  ‰j#  ‰jŸ  ‰jæ  ‰j  ‰uh}”(j(  h£jJ  hÝj   jP  jœ  j  jã  j¢  j  jé  uŒfootnote_refs”}”Œcitation_refs”}”Œautofootnotes”]”Œautofootnote_refs”]”Œsymbol_footnotes”]”Œsymbol_footnote_refs”]”Œ	footnotes”]”Œ	citations”]”Œautofootnote_start”KŒsymbol_footnote_start”K Œ
id_counter”Œcollections”ŒCounter”“”}”…”R”Œparse_messages”]”Œtransform_messages”]”Œtransformer”NŒinclude_log”]”Œ
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