From a0a4959eb4e94ce98ee5549dd7d1296d41162ca8 Mon Sep 17 00:00:00 2001 From: Jorge Sanjuan Date: Tue, 31 Jul 2018 13:28:45 +0100 Subject: ALSA: usb-audio: Operate UAC3 Power Domains in PCM callbacks Make use of UAC3 Power Domains associated to an Audio Streaming path within the PCM's logic. This means, when there is no audio being transferred (pcm is closed), the host will set the Power Domain associated to that substream to state D1. When audio is being transferred (from hw_params onwards), the Power Domain will be set to D0 state. This is the way the host lets the device know which Terminal is going to be actively used and it is for the device to manage its own internal resources on that UAC3 Power Domain. Note the resume method now sets the Power Domain to D1 state as resuming the device doesn't mean audio streaming will occur. Signed-off-by: Jorge Sanjuan Signed-off-by: Takashi Iwai --- sound/usb/stream.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'sound/usb/stream.c') diff --git a/sound/usb/stream.c b/sound/usb/stream.c index c0567fa1e84b..8fe3b0e00e45 100644 --- a/sound/usb/stream.c +++ b/sound/usb/stream.c @@ -110,8 +110,12 @@ static void snd_usb_init_substream(struct snd_usb_stream *as, if (fp->channels > subs->channels_max) subs->channels_max = fp->channels; - if (pd) + if (pd) { subs->str_pd = pd; + /* Initialize Power Domain to idle status D1 */ + snd_usb_power_domain_set(subs->stream->chip, pd, + UAC3_PD_STATE_D1); + } snd_usb_preallocate_buffer(subs); } -- cgit v1.2.3