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ALSA: docs: Add documents for recently changes in snd-usb-audio
Changed: - ignore_ctl_error - lowlatency - skip_validation - quirk_flags[19:24] [ corrected a typo -- tiwai ] Signed-off-by: Cryolitia PukNgae <[email protected]> Link: https://patch.msgid.link/[email protected] Signed-off-by: Takashi Iwai <[email protected]>
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Documentation/sound/alsa-configuration.rst

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@@ -2253,8 +2253,15 @@ device_setup
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Default: 0x0000
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ignore_ctl_error
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Ignore any USB-controller regarding mixer interface (default: no)
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``ignore_ctl_error=1`` may help when you get an error at accessing
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the mixer element such as URB error -22. This happens on some
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buggy USB device or the controller. This workaround corresponds to
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the ``quirk_flags`` bit 14, too.
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autoclock
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Enable auto-clock selection for UAC2 devices (default: yes)
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lowlatency
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Enable low latency playback mode (default: yes).
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Could disable it to switch back to the old mode if face a regression.
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quirk_alias
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Quirk alias list, pass strings like ``0123abcd:5678beef``, which
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applies the existing quirk for the device 5678:beef to a new
@@ -2284,6 +2291,11 @@ delayed_register
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The driver prints a message like "Found post-registration device
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assignment: 1234abcd:04" for such a device, so that user can
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notice the need.
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skip_validation
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Skip unit descriptor validation (default: no).
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The option is used to ignores the validation errors with the hexdump
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of the unit descriptor instead of a driver probe error, so that we
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can check its details.
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quirk_flags
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Contains the bit flags for various device specific workarounds.
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Applied to the corresponding card index.
@@ -2307,17 +2319,26 @@ quirk_flags
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* bit 16: Set up the interface at first like UAC1
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* bit 17: Apply the generic implicit feedback sync mode
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* bit 18: Don't apply implicit feedback sync mode
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* bit 19: Don't closed interface during setting sample rate
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* bit 20: Force an interface reset whenever stopping & restarting
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a stream
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* bit 21: Do not set PCM rate (frequency) when only one rate is
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available for the given endpoint.
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* bit 22: Set the fixed resolution 16 for Mic Capture Volume
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* bit 23: Set the fixed resolution 384 for Mic Capture Volume
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* bit 24: Set minimum volume control value as mute for devices
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where the lowest playback value represents muted state instead
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of minimum audible volume
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This module supports multiple devices, autoprobe and hotplugging.
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NB: ``nrpacks`` parameter can be modified dynamically via sysfs.
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Don't put the value over 20. Changing via sysfs has no sanity
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check.
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NB: ``ignore_ctl_error=1`` may help when you get an error at accessing
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the mixer element such as URB error -22. This happens on some
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buggy USB device or the controller. This workaround corresponds to
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the ``quirk_flags`` bit 14, too.
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NB: ``ignore_ctl_error=1`` just provides a quick way to work around the
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issues. If you have a buggy device that requires these quirks, please
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report it to the upstream.
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NB: ``quirk_alias`` option is provided only for testing / development.
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If you want to have a proper support, contact to upstream for

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