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author | Linus Torvalds <torvalds@linux-foundation.org> | 2015-06-26 03:15:18 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-06-26 03:15:18 +0300 |
commit | 4570a37169d4b44d316f40b2ccc681dc93fedc7b (patch) | |
tree | cafffb586c60dddfb04b8619fa1ae0e859600de7 /Documentation/sound/alsa/Jack-Controls.txt | |
parent | f7b08217c755e88a29b5bd53b4a1d10cd8b3c5f8 (diff) | |
parent | 60b93030b44a8c2cd015cebe5624fd7552ec67ec (diff) | |
download | linux-4570a37169d4b44d316f40b2ccc681dc93fedc7b.tar.xz |
Merge tag 'sound-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
Pull sound updates from Takashi Iwai:
"It was a busy development cycle at this time, as you can see a wide
range of changes in diffstat. There are no big changes but many
refactoring and improvements. Here we go some highlights:
ALSA core:
- Procfs codes were cleaned up to use seq_file
- Procfs can be opt out via Kconfig (only for EXPERT)
- Two types of jack API were unified finally; now both kctl and input
jack devs are handled via a single function call.
HD-audio:
- Continued code restructuring for the future ASoC driver; now HDA
controller driver is split to a core helper module.
- Preliminary codes for Skylake audio support in HDA core.
- Proper i915 gfx power well management for SKL & co
- Enabled runtime PM as default for Intel HDMI/DP codecs
- Newer Tegra chip supports
- More quirks for Dell headsets, Alienware (with CA0132), etc.
- A couple of DRM ELD helper API functions
ASoC:
- Support for loading ASoC topology maps from firmware, intended to
be used to allow self-describing DSP firmware images to be built
which can map controls added by the DSP to userspace without the
kernel needing to know about individual DSP firmwares
- Lots of refactoring to avoid direct access to snd_soc_codec where
it's not needed supporting future refactoring
- Big refactoring, cleanup and enhancement for the Wolfson ADSP
driver
- Cleanup series for TI TAS2552 and R-CAR drivers
- Fixes and improvements on RT56xx codecs
- Support for TI TAS571x power amplifiers
- Support for Qualcomm APQ8016 and ZTE ZX296702 SoCs
- Support for x86 systems with RT5650 and Qualcomm Storm
- Support for Mediatek AFE (Audio Front End) unit
- Other various small fixes to ASoC codec drivers
Firewire:
- Enhanced to allow non-blocking streams to use timestamp
synchronization
- Improve support for DM1500 and BeBoBv3
Misc:
- Cleanup of old pci API functions over all PCI sound drivers
- Fix long-standing regression of the old powermac i2c setup"
* tag 'sound-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (533 commits)
ALSA: pcm: Fix pcm_class sysfs output
ALSA: hda-beep: Update authors dead email address
ASoC: wm_adsp: Move DSP Rate controls into the codec
ASoC: wm8995: Fix setting sysclk for WM8995_SYSCLK_MCLK2 case
ALSA: hda: provide default bus io ops extended hdac
ALSA: hda: add hda link cleanup routine
ALSA: hda: add hdac_ext stream creation and cleanup routines
ASoC: rsrc-card: remove unused ret
ALSA: HDAC: move SND_HDA_PREALLOC_SIZE to core
ASoC: mediatek: Add machine driver for rt5650 rt5676 codec
ASoC: mediatek: Add machine driver for MAX98090 codec
ASoC: mediatek: Add AFE platform driver
ASoC: rsnd: remove io from rsnd_mod
ASoC: rsnd: move rsnd_mod_is_working() to rsnd_io_is_working()
ASoC: rsnd: don't use rsnd_mod_to_io() on snd_kcontrol
ASoC: rsnd: don't use rsnd_mod_to_io() on rsnd_src_xxx()
ASoC: rsnd: don't use rsnd_mod_to_io() on rsnd_ssi_xxx()
ASoC: rsnd: don't use rsnd_mod_to_io() on rsnd_dma_xxx()
ASoC: rsnd: don't use rsnd_mod_to_io() on rsnd_get_adinr()
ASoC: rsnd: add common interrupt handler for SSI/SRC/DMA
...
Diffstat (limited to 'Documentation/sound/alsa/Jack-Controls.txt')
-rw-r--r-- | Documentation/sound/alsa/Jack-Controls.txt | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/Documentation/sound/alsa/Jack-Controls.txt b/Documentation/sound/alsa/Jack-Controls.txt new file mode 100644 index 000000000000..fe1c5e0c8555 --- /dev/null +++ b/Documentation/sound/alsa/Jack-Controls.txt @@ -0,0 +1,43 @@ +Why we need Jack kcontrols +========================== + +ALSA uses kcontrols to export audio controls(switch, volume, Mux, ...) +to user space. This means userspace applications like pulseaudio can +switch off headphones and switch on speakers when no headphones are +pluged in. + +The old ALSA jack code only created input devices for each registered +jack. These jack input devices are not readable by userspace devices +that run as non root. + +The new jack code creates embedded jack kcontrols for each jack that +can be read by any process. + +This can be combined with UCM to allow userspace to route audio more +intelligently based on jack insertion or removal events. + +Jack Kcontrol Internals +======================= + +Each jack will have a kcontrol list, so that we can create a kcontrol +and attach it to the jack, at jack creation stage. We can also add a +kcontrol to an existing jack, at anytime when required. + +Those kcontrols will be freed automatically when the Jack is freed. + +How to use jack kcontrols +========================= + +In order to keep compatibility, snd_jack_new() has been modified by +adding two params :- + + - @initial_kctl: if true, create a kcontrol and add it to the jack + list. + - @phantom_jack: Don't create a input device for phantom jacks. + +HDA jacks can set phantom_jack to true in order to create a phantom +jack and set initial_kctl to true to create an initial kcontrol with +the correct id. + +ASoC jacks should set initial_kctl as false. The pin name will be +assigned as the jack kcontrol name. |