[PATCH 0/9] ALSA: usb-audio: Add quirks for linear volume devices and deconflict VID

[Rong Zhang]

Some quirky devices tune their volume by linearly tuning the voltage
level (linear volume). In other words, such devices has a linear TLV
mapping of DECLARE_TLV_DB_LINEAR(scale, TLV_DB_GAIN_MUTE, 0).

The series mainly adds quirk flags MIXER_PLAYBACK_LINEAR_VOL and
MIXER_CAPTURE_LINEAR_VOL to represent this case respectively for
playback and capture mixers. Afterward, apply these quirk flags on them.

Some MV-SILICON devices with these quirks also have another quirk: VID
conflicts with Focusrite Novation (0x1235). Hence, add support for
string-descriptor-based quirk table entries and define an entry for MV-
SILICON to deconflict them.

Some improvements to the logic of volume range checks is also included
in the series to help identify quirky devices with linear volume.

Rong Zhang (9):
  Revert "ALSA: usb: Increase volume range that triggers a warning"
  ALSA: usb-audio: Add helper function for volume range checks
  ALSA: usb-audio: Improve volume range checks
  ALSA: usb-audio: Support string-descriptor-based quirk table entry
  ALSA: usb-audio: Deconflict VID between Focusrite Novation &
    MV-SILICON
  ALSA: doc: Add doc for QUIRK_FLAG_SKIP_IFACE_SETUP of snd-usb-audio
  ALSA: usb-audio: Add QUIRK_FLAG_MIXER_{PLAYBACK,CAPTURE}_LINEAR_VOL
  ALSA: usb-audio: Add linear volume quirk for Hotone Audio Pulze Mini
  ALSA: usb-audio: Apply linear volume quirk on MV-SILICON devices

 Documentation/sound/alsa-configuration.rst | 11 +++
 sound/usb/mixer.c                          | 84 ++++++++++++++++----
 sound/usb/mixer_quirks.c                   | 56 ++++++++++++++
 sound/usb/quirks.c                         | 89 ++++++++++++++++++++++
 sound/usb/usbaudio.h                       | 12 +++
 5 files changed, 237 insertions(+), 15 deletions(-)


base-commit: 39c633261414f12cb533a8b802ee57e2d2e3c482
-- 
2.51.0