Add the brief document for describing the MIDI 2.0 implementation on
Linux kernel. Both rawmidi and sequencer API extensions are
described.
Acked-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20230523075358.9672-38-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This change adds audio jack injection feature through debugfs, with
this feature, we could validate alsa userspace changes by injecting
plugin or plugout events to the non-phantom audio jacks.
With this change, the sound core will build the folders
$debugfs_mount_dir/sound/cardN if SND_DEBUG and DEBUG_FS are enabled.
And if users also enable the SND_JACK_INJECTION_DEBUG, the jack
injection nodes will be built in the folder cardN like below:
$tree $debugfs_mount_dir/sound
$debugfs_mount_dir/sound
├── card0
│ ├── HDMI_DP_pcm_10_Jack
│ │ ├── jackin_inject
│ │ ├── kctl_id
│ │ ├── mask_bits
│ │ ├── status
│ │ ├── sw_inject_enable
│ │ └── type
...
│ └── HDMI_DP_pcm_9_Jack
│ ├── jackin_inject
│ ├── kctl_id
│ ├── mask_bits
│ ├── status
│ ├── sw_inject_enable
│ └── type
└── card1
├── HDMI_DP_pcm_5_Jack
│ ├── jackin_inject
│ ├── kctl_id
│ ├── mask_bits
│ ├── status
│ ├── sw_inject_enable
│ └── type
...
├── Headphone_Jack
│ ├── jackin_inject
│ ├── kctl_id
│ ├── mask_bits
│ ├── status
│ ├── sw_inject_enable
│ └── type
└── Headset_Mic_Jack
├── jackin_inject
├── kctl_id
├── mask_bits
├── status
├── sw_inject_enable
└── type
The nodes kctl_id, mask_bits, status and type are read-only, users
could check jack or jack_kctl's information through them.
The nodes sw_inject_enable and jackin_inject are directly used for
injection. The sw_inject_enable is read-write, users could check if
software injection is enabled or not on this jack, and users could
echo 1 or 0 to enable or disable software injection on this jack. Once
the injection is enabled, the jack will not change by hardware events
anymore, once the injection is disabled, the jack will restore the
last reported hardware events to the jack. The jackin_inject is
write-only, if the injection is enabled, users could echo 1 or 0 to
this node to inject plugin or plugout events to this jack.
For the detailed usage information on these nodes, please refer to
Documentation/sound/designs/jack-injection.rst.
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Signed-off-by: Hui Wang <hui.wang@canonical.com>
Link: https://lore.kernel.org/r/20210127085639.74954-2-hui.wang@canonical.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
In PCM interface/protocol for userspace, parameters of runtime for PCM
substream is decided by an interaction between applications and ALSA
PCM core. In former commits, some tracepoints were added to probe a part
of the interaction.
This commit adds a documentation about the interaction and the
tracepoints.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Converted from an ancient plain HTML document. It's much readable now!
Put to designs subdirectory with a slight rename.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
A simple conversion from a text file.
Put into designs subdirectory, although it's mostly relevant with
HD-audio.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
A simple conversion from a text file.
A new subidrectory, Documentation/sound/designs, was created to put
this document. The other API design and implementation docuemnts
will be put to that directory in later commits.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Takashi Iwai