summaryrefslogtreecommitdiffstats
path: root/sound/usb/pcm.c
diff options
context:
space:
mode:
authorTakashi Iwai <tiwai@suse.de>2021-09-29 10:08:40 +0200
committerTakashi Iwai <tiwai@suse.de>2021-09-30 13:55:22 +0200
commitbceee75387554f682638e719d1ea60125ea78cea (patch)
tree89a367c7c3b2e7e684eb567e4e4f5e3b6733856a /sound/usb/pcm.c
parentALSA: usb-audio: Disable low-latency playback for free-wheel mode (diff)
downloadlinux-bceee75387554f682638e719d1ea60125ea78cea.tar.xz
linux-bceee75387554f682638e719d1ea60125ea78cea.zip
ALSA: usb-audio: Disable low-latency mode for implicit feedback sync
When a playback stream runs in the implicit feedback mode, its operation is passive and won't start unless the capture packet is received. This behavior contradicts with the low-latency playback mode, and we should turn off lowlatency_playback flag accordingly. In theory, we may take the low-latency mode when the playback-first quirk is set, but it still conflicts with the later operation with the fixed packet numbers, so it's disabled all together for now. Link: https://lore.kernel.org/r/20210929080844.11583-6-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb/pcm.c')
-rw-r--r--sound/usb/pcm.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 84b03a32ee23..ec7eeb1b82b8 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -595,6 +595,9 @@ static int lowlatency_playback_available(struct snd_pcm_runtime *runtime,
/* free-wheeling mode? (e.g. dmix) */
if (runtime->stop_threshold > runtime->buffer_size)
return false;
+ /* implicit feedback mode has own operation mode */
+ if (snd_usb_endpoint_implicit_feedback_sink(subs->data_endpoint))
+ return false;
/* too short periods? */
if (subs->data_endpoint->nominal_queue_size >= subs->buffer_bytes)
return false;