From: Rong Zhang Date: Tue, 26 May 2026 17:49:23 +0000 (+0800) Subject: ALSA: doc: usb-audio: Add doc for QUIRK_FLAG_IFB_SILENCE_ON_EMPTY X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=06363f96e3d6b54ff7b5d2ce85cab95bd5e874b0;p=thirdparty%2Flinux.git ALSA: doc: usb-audio: Add doc for QUIRK_FLAG_IFB_SILENCE_ON_EMPTY QUIRK_FLAG_IFB_SILENCE_ON_EMPTY was introduced into usb-audio before without appropriate documentation, so add it. Fixes: a23812004228 ("ALSA: usb-audio: add IFB_SILENCE_ON_EMPTY quirk for Behringer Flow 8") Signed-off-by: Rong Zhang Link: https://patch.msgid.link/20260527-uac-quirk-get-cur-vol-v1-1-e9362b712e5e@rong.moe Signed-off-by: Takashi Iwai --- diff --git a/Documentation/sound/alsa-configuration.rst b/Documentation/sound/alsa-configuration.rst index f75f087639415..4b30cd63c5a5a 100644 --- a/Documentation/sound/alsa-configuration.rst +++ b/Documentation/sound/alsa-configuration.rst @@ -2383,6 +2383,12 @@ quirk_flags ``V(x) = k * x``; ``dB(x) = 20 * log10(x)``. Overrides bit 24 * bit 28: ``mixer_capture_linear_vol`` Similar to bit 27 but for capture streams. Overrides bit 25 + * bit 29: ``ifb_silence_on_empty`` + In implicit feedback mode, when an entire capture URB returns with + all iso_frame_desc[i].status != 0 (bytes==0), do not silently return + from snd_usb_handle_sync_urb. Instead fall through and enqueue a + packet_info containing only size-0 packets, so the OUT ring keeps + moving (emits silence). Needed by Behringer Flow 8 (1397:050c). This module supports multiple devices, autoprobe and hotplugging.