[PATCH v2 3/3] ALSA: doc: add docs about device_device_quirk_flags in snd-usb-audio

Cryolitia PukNgae via B4 Relay
2025-09-12T06:49:11Z

From: Cryolitia PukNgae <cryolitia@uniontech.com>

Just briefly described about the new option.

Signed-off-by: Cryolitia PukNgae <cryolitia@uniontech.com>
---
Documentation/sound/alsa-configuration.rst | 105 ++++++++++++++++++++---------
1 file changed, 73 insertions(+), 32 deletions(-)

diff --git a/Documentation/sound/alsa-configuration.rst b/Documentation/sound/alsa-configuration.rst
index a2fb8ed251dd0294e7a62209ca15d5c32c6adfae..060dfbd4197d3134f20d3d86300d97b14071eee9 100644
--- a/Documentation/sound/alsa-configuration.rst
+++ b/Documentation/sound/alsa-configuration.rst
@@ -2296,40 +2296,81 @@ skip_validation
The option is used to ignore the validation errors with the hexdump
of the unit descriptor instead of a driver probe error, so that we
can check its details.
+device_device_quirk_flags
+ The option povides a refined and flexible control for applying quirk
+ flags. It allows to specify the quirk flags for each device, and could
+ be modified dynamically via sysfs.
+ The option accepts a string in the format of ``VID1:PID1:FLAGS1;VID2:PID2:
+ FLAGS2;...``, where ``VIDx`` and ``PIDx`` specify the device, and
+ ``FLAGSx`` specify the flags to be applied. ``VIDx`` and ``PIDx`` are
+ 4-digit hexadecimal numbers, and could be specified as ``*`` to match any
+ value. ``FLAGSx`` could be a set of flags given by name, separated by
+ comma, or a hexadecimal number representing the bit flags. The available
+ flag names are listed above. An exclamation mark could be prefixed to a
+ flag name to negate the flag. For example,
+ ``1234:abcd:mixer_playback_min_mute,!ignore_ctl_error;*:*:0x01;``
+ applies the ``mixer_playback_min_mute`` flag and clears the
+ ``ignore_ctl_error`` flag for the device 1234:abcd, and applies
+ the ``skip_sample_rate`` flag for all devices.
quirk_flags
Contains the bit flags for various device specific workarounds.
Applied to the corresponding card index.

- * bit 0: Skip reading sample rate for devices
- * bit 1: Create Media Controller API entries
- * bit 2: Allow alignment on audio sub-slot at transfer
- * bit 3: Add length specifier to transfers
- * bit 4: Start playback stream at first in implement feedback mode
- * bit 5: Skip clock selector setup
- * bit 6: Ignore errors from clock source search
- * bit 7: Indicates ITF-USB DSD based DACs
- * bit 8: Add a delay of 20ms at each control message handling
- * bit 9: Add a delay of 1-2ms at each control message handling
- * bit 10: Add a delay of 5-6ms at each control message handling
- * bit 11: Add a delay of 50ms at each interface setup
- * bit 12: Perform sample rate validations at probe
- * bit 13: Disable runtime PM autosuspend
- * bit 14: Ignore errors for mixer access
- * bit 15: Support generic DSD raw U32_BE format
- * 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
- * bit 25: Be similar to bit 24 but for capture streams
+ * bit 0: ``get_sample_rate``
+ Skip reading sample rate for devices
+ * bit 1: ``share_media_device``
+ Create Media Controller API entries
+ * bit 2: ``align_transfer``
+ Allow alignment on audio sub-slot at transfer
+ * bit 3: ``tx_length``
+ Add length specifier to transfers
+ * bit 4: ``playback_first``
+ Start playback stream at first in implement feedback mode
+ * bit 5: ``skip_clock_selector``
+ Skip clock selector setup
+ * bit 6: ``ignore_clock_source``
+ Ignore errors from clock source search
+ * bit 7: ``itf_usb_dsd_dac``
+ Indicates ITF-USB DSD based DACs
+ * bit 8: ``ctl_msg_delay``
+ Add a delay of 20ms at each control message handling
+ * bit 9: ``ctl_msg_delay_1m``
+ Add a delay of 1-2ms at each control message handling
+ * bit 10: ``ctl_msg_delay_5m``
+ Add a delay of 5-6ms at each control message handling
+ * bit 11: ``iface_delay``
+ Add a delay of 50ms at each interface setup
+ * bit 12: ``validate_rates``
+ Perform sample rate validations at probe
+ * bit 13: ``disable_autosuspend``
+ Disable runtime PM autosuspend
+ * bit 14: ``ignore_ctl_error``
+ Ignore errors for mixer access
+ * bit 15: ``dsd_raw``
+ Support generic DSD raw U32_BE format
+ * bit 16: ``set_iface_first``
+ Set up the interface at first like UAC1
+ * bit 17: ``generic_implicit_fb``
+ Apply the generic implicit feedback sync mode
+ * bit 18: ``skip_implicit_fb``
+ Don't apply implicit feedback sync mode
+ * bit 19: ``iface_skip_close``
+ Don't closed interface during setting sample rate
+ * bit 20: ``force_iface_reset``
+ Force an interface reset whenever stopping & restarting a stream
+ * bit 21: ``fixed_rate``
+ Do not set PCM rate (frequency) when only one rate is available
+ for the given endpoint
+ * bit 22: ``mic_res_16``
+ Set the fixed resolution 16 for Mic Capture Volume
+ * bit 23: ``mic_res_384``
+ Set the fixed resolution 384 for Mic Capture Volume
+ * bit 24: ``mixer_playback_min_mute``
+ Set minimum volume control value as mute for devices where the
+ lowest playback value represents muted state instead of minimum
+ audible volume
+ * bit 25: ``mixer_capture_min_mute``
+ Be similar to bit 24 but for capture streams

This module supports multiple devices, autoprobe and hotplugging.

@@ -2344,8 +2385,8 @@ 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
adding the matching quirk in the driver code statically.
-Ditto for ``quirk_flags``. If a device is known to require specific
-workarounds, please report to the upstream.
+Ditto for ``quirk_flags`` and ``device_device_quirk_flags``. If a device
+is known to require specific workarounds, please report to the upstream.

Module snd-usb-caiaq
--------------------

--
2.51.0