The recent support for the improved low-latency playback mode applied the SNDRV_PCM_INFO_EXPLICIT_SYNC flag for the target streams, but this was a slight overkill. The use of the flag above disables effectively both PCM status and control mmaps, while basically what we want to track is only about the appl_ptr update.

For less restriction, use a more proper flag, SNDRV_PCM_INFO_SYNC_APPLPTR instead, which disables only the control mmap.

Fixes: d5f871f89e21 ("ALSA: usb-audio: Improved lowlatency playback support") Signed-off-by: Takashi Iwai tiwai@suse.de --- sound/usb/pcm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c index 3bb095a3c9b6..95ec8eec1bb0 100644 --- a/sound/usb/pcm.c +++ b/sound/usb/pcm.c @@ -1102,7 +1102,7 @@ static int snd_usb_pcm_open(struct snd_pcm_substream *substream) /* need an explicit sync to catch applptr update in low-latency mode */ if (direction == SNDRV_PCM_STREAM_PLAYBACK && as->chip->lowlatency) - runtime->hw.info |= SNDRV_PCM_INFO_EXPLICIT_SYNC; + runtime->hw.info |= SNDRV_PCM_INFO_SYNC_APPLPTR; runtime->private_data = subs; subs->pcm_substream = substream; /* runtime PM is also done there */