linux-kernel - Re: [RFC PATCH v2 5/5] ASoC: apple: Add macaudio machine driver

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <YqILv21K+tZ00Qhx@sirena.org.uk>
Date:   Thu, 9 Jun 2022 16:03:27 +0100
From:   Mark Brown <broonie@...nel.org>
To:     Martin Povišer <povik+lin@...ebit.org>
Cc:     Liam Girdwood <lgirdwood@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>, alsa-devel@...a-project.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Mark Kettenis <kettenis@...nbsd.org>,
        Hector Martin <marcan@...can.st>,
        Sven Peter <sven@...npeter.dev>, asahi@...ts.linux.dev
Subject: Re: [RFC PATCH v2 5/5] ASoC: apple: Add macaudio machine driver

On Thu, Jun 09, 2022 at 03:42:09PM +0200, Martin Povišer wrote:
> > On 9. 6. 2022, at 15:16, Mark Brown <broonie@...nel.org> wrote:

> > As far as I can tell this demux is entirely software based - why not
> > just expose the routing control to userspace and let it handle
> > switching (which I suspect may be more featureful than what's
> > implemented here)?

> Well, userspace should have the other two muxes at its disposal to
> implement any routing/switching it wishes -- but in addition we are
> also offering letting kernel take care of the switching, by pointing
> the muxes to the demux.

> I assume (but I don’t know the extent of what’s possible with UCM files),
> that this will be of some value to users running plain ALSA with no
> sound server.

That's basically no userspaces at this point TBH.  I'm not convinced
it's a good idea to be adding custom code for that use case.

> > This should be integrated with the core jack detection stuff in
> > soc-jack.c and/or the core stuff that's wrapping - that way you'll
> > ensure that events are generated and status readable via all the
> > interfaces userspace might be looking for.  The ASoC stuff also has some
> > DAPM integration for turning on/off outputs which might DTRT for you if
> > you do need it in kernel.

> Aren’t all the right events to userspace generated already by the
> codec calling snd_soc_jack_report?

I wasn't able to find any references to snd_soc_jack_report() in your
series?

> I looked at the existing DAPM integration but I couldn’t figure out
> how to switch the demux with it.

Yes, it won't do that.  If you can't stream the same audio to both then
you'd need something else.

Download attachment "signature.asc" of type "application/pgp-signature" (489 bytes)