alsa-udev: support alsa.ignore-dB

Some sound cards are only adapted for Android/macOS and other
systems, without considering Linux. The hardware-reported dB
volume is incorrect (while the percentage volume is normal).
Add support for the ignore-dB option to simplify compatibility.

For example, the 3206:0798 HP SIMGOT GEW1 Sound Card reports:

numid=4,iface=MIXER,name='PCM Playback Volume'
  ; type=INTEGER,access=rw---R--,values=2,min=0,max=100,step=0
  : values=100,100
  | dBminmax-min=0.00dB,max=0.39dB

This dB value does not match actual audio perception, and the
vendor attributed this issue to non-target system compatibility.
This commit is contained in:
qaqland 2026-03-07 13:25:28 +08:00
parent 70b7b42f5d
commit d1c372f5ee

View file

@ -538,6 +538,9 @@ static int emit_added_object_info(struct impl *this, struct card *card)
if ((str = udev_device_get_property_value(udev_device, "ACP_PROFILE_SET")) && *str)
items[n_items++] = SPA_DICT_ITEM_INIT(SPA_KEY_DEVICE_PROFILE_SET, str);
if ((str = udev_device_get_property_value(udev_device, "ACP_IGNORE_DB")) && *str)
items[n_items++] = SPA_DICT_ITEM_INIT(SPA_KEY_API_ALSA_IGNORE_DB, str);
if ((str = udev_device_get_property_value(udev_device, "SOUND_CLASS")) && *str)
items[n_items++] = SPA_DICT_ITEM_INIT(SPA_KEY_DEVICE_CLASS, str);