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| author | Ruslan Bilovol <ruslan.bilovol@gmail.com> | 2021-06-04 00:01:03 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-06-09 11:26:49 +0200 |
| commit | 40c73b30546e759bedcec607fedc2d4be954508f (patch) | |
| tree | 1705efa2c413c6f71900323dc7a2b7039583cb60 /Documentation/usb | |
| parent | 24f779dac8f3efb9629adc0e486914d93dc45517 (diff) | |
| download | linux-stable-40c73b30546e759bedcec607fedc2d4be954508f.tar.gz linux-stable-40c73b30546e759bedcec607fedc2d4be954508f.tar.bz2 linux-stable-40c73b30546e759bedcec607fedc2d4be954508f.zip | |
usb: gadget: f_uac2: add adaptive sync support for capture
Current f_uac2 USB OUT (aka 'capture') synchronization
implements 'ASYNC' scenario which means USB Gadget has
it's own freerunning clock and can update Host about
real clock frequency through feedback endpoint so Host
can align number of samples sent to the USB gadget to
prevent overruns/underruns
In case if Gadget can has no it's internal clock and
can consume audio samples at any rate (for example,
on the Gadget side someone records audio directly to
a file, or audio samples are played through an
external DAC as soon as they arrive), UAC2 spec
suggests 'ADAPTIVE' synchronization type.
Change UAC2 driver to make it configurable through
additional 'c_sync' configfs file.
Default remains 'asynchronous' with possibility to
switch it to 'adaptive'
Signed-off-by: Ruslan Bilovol <ruslan.bilovol@gmail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20210603220104.1216001-3-jbrunet@baylibre.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/usb')
| -rw-r--r-- | Documentation/usb/gadget-testing.rst | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/Documentation/usb/gadget-testing.rst b/Documentation/usb/gadget-testing.rst index 2085e7b24eeb..f5a12667bd41 100644 --- a/Documentation/usb/gadget-testing.rst +++ b/Documentation/usb/gadget-testing.rst @@ -728,6 +728,7 @@ The uac2 function provides these attributes in its function directory: c_chmask capture channel mask c_srate capture sampling rate c_ssize capture sample size (bytes) + c_sync capture synchronization type (async/adaptive) p_chmask playback channel mask p_srate playback sampling rate p_ssize playback sample size (bytes) |