Messages in this thread | | | Subject | Re: [PATCH v2 4/4] ALSA: usb-audio: Operate UAC3 Power Domains in PCM callbacks | From | Jorge <> | Date | Mon, 30 Jul 2018 17:09:38 +0100 |
| |
On 30/07/18 14:13, Takashi Iwai wrote: > On Mon, 30 Jul 2018 11:23:36 +0200, > Jorge Sanjuan wrote: >> >> 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. > > I guess we need the power state transition to D0 also in prepare > callback. The recovery from suspend doesn't need hw_params call but > just prepare -> trigger.
Right! Shouldn't it then be enough to just go to D0 on .prepare? I,e. Move the state transition from .hw_params to .prepare.
Jorge
> > One could think of implementing into the trigger, but since the > transition needs some delay, prepare callback would be a better > choice, as it seems. > > > thanks, > > Takashi >
-- Jorge Sanjuan, Software Engineer Codethink Ltd http://www.codethink.co.uk/ We respect your privacy. See https://www.codethink.co.uk/privacy.html
| |