Commit 78811dd5 authored by Cryolitia PukNgae's avatar Cryolitia PukNgae Committed by Takashi Iwai
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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: default avatarCryolitia PukNgae <cryolitia@uniontech.com>
Link: https://patch.msgid.link/20250829-sound-doc-v1-1-e0110452b03d@uniontech.com


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 3e93d5bb

Documentation/sound/alsa-configuration.rst

+25 −4
Original line number Diff line number Diff line
@@ -2253,8 +2253,15 @@ device_setup 
    Default: 0x0000 

ignore_ctl_error

    Ignore any USB-controller regarding mixer interface (default: no)

    ``ignore_ctl_error=1`` may help when you get an error at accessing

    the mixer element such as URB error -22.  This happens on some

    buggy USB device or the controller.  This workaround corresponds to

    the ``quirk_flags`` bit 14, too.

autoclock

    Enable auto-clock selection for UAC2 devices (default: yes)

lowlatency

    Enable low latency playback mode (default: yes).

    Could disable it to switch back to the old mode if face a regression.

quirk_alias

    Quirk alias list, pass strings like ``0123abcd:5678beef``, which

    applies the existing quirk for the device 5678:beef to a new
@@ -2284,6 +2291,11 @@ delayed_register 
    The driver prints a message like "Found post-registration device

    assignment: 1234abcd:04" for such a device, so that user can

    notice the need.

skip_validation

    Skip unit descriptor validation (default: no).

    The option is used to ignores the validation errors with the hexdump

    of the unit descriptor instead of a driver probe error, so that we

    can check its details.

quirk_flags

    Contains the bit flags for various device specific workarounds.

    Applied to the corresponding card index.
@@ -2307,6 +2319,16 @@ quirk_flags 
        * bit 16: Set up the interface at first like UAC1

        * bit 17: Apply the generic implicit feedback sync mode

        * bit 18: Don't apply implicit feedback sync mode

        * bit 19: Don't closed interface during setting sample rate

        * bit 20: Force an interface reset whenever stopping & restarting

          a stream

        * bit 21: Do not set PCM rate (frequency) when only one rate is

          available for the given endpoint.

        * bit 22: Set the fixed resolution 16 for Mic Capture Volume

        * bit 23: Set the fixed resolution 384 for Mic Capture Volume

        * bit 24: Set minimum volume control value as mute for devices

          where the lowest playback value represents muted state instead

          of minimum audible volume



This module supports multiple devices, autoprobe and hotplugging.
@@ -2314,10 +2336,9 @@ NB: ``nrpacks`` parameter can be modified dynamically via sysfs. 
Don't put the value over 20.  Changing via sysfs has no sanity

check.



NB: ``ignore_ctl_error=1`` may help when you get an error at accessing

the mixer element such as URB error -22.  This happens on some

buggy USB device or the controller.  This workaround corresponds to

the ``quirk_flags`` bit 14, too.

NB: ``ignore_ctl_error=1`` just provides a quick way to work around the

issues.  If you have a buggy device that requires these quirks, please

report it to the upstream.



NB: ``quirk_alias`` option is provided only for testing / development.

If you want to have a proper support, contact to upstream for