[alsa-devel] [PATCH 06/11] ucm: docs: Add DisableSoftwareVolume

[Curtis Malainey]

On Mon, Nov 11, 2019 at 7:22 AM Jaroslav Kysela <perex at perex.cz> wrote:
>
> Dne 07. 11. 19 v 2:58 Curtis Malainey napsal(a):
> > Some userspace audio servers might default to software volume, this
> > allows the ucm to force its behaviour
> >
> > Signed-off-by: Curtis Malainey <cujomalainey at chromium.org>
> > ---
> >   include/use-case.h | 2 ++
> >   1 file changed, 2 insertions(+)
> >
> > diff --git a/include/use-case.h b/include/use-case.h
> > index 05628303..1aeaf9d4 100644
> > --- a/include/use-case.h
> > +++ b/include/use-case.h
> > @@ -334,6 +334,8 @@ int snd_use_case_get_list(snd_use_case_mgr_t *uc_mgr,
> >    *      - This is used on platform where reported buffer level is not accurate.
> >    *        E.g. "512", which holds 512 samples in device buffer. Note: this will
> >    *        increase latency.
> > + *   - DisableSoftwareVolume
> > + *      - Set to "1" to force userspace to use hardware volume controls
> >    */
> >   int snd_use_case_get(snd_use_case_mgr_t *uc_mgr,
> >                        const char *identifier,
> >
>
>
> My understanding is that if the hardware volume controls are defined in UCM,
> then the UCM user (audio server) should use them. Otherwise, the software
> volume control should be applied. I don't see the reason to have this info
> doubled.
>
>                                         Jaroslav
>
+Jimmy Cheng-Yi Chiang can you clarify in what context CRAS might need
this value? The only cases I see are for Chat 150 C and Jabra SPEAK
810. There are no volume mixers associated with these files.
> --
> Jaroslav Kysela <perex at perex.cz>
> Linux Sound Maintainer; ALSA Project; Red Hat, Inc.