lkml.org 
[lkml]   [2018]   [Jul]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2 4/4] ALSA: usb-audio: Operate UAC3 Power Domains in PCM callbacks
On Mon, 30 Jul 2018 18:09:38 +0200,
Jorge wrote:
>
>
>
> 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.

Does the power domain transition needed for setting the format, EP,
etc done in set_format()? If yes, we need D0 in hw_parmas as well.


thanks,

Takashi

\
 
 \ /
  Last update: 2018-07-30 18:12    [W:0.072 / U:1.036 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site