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From: "Christian König" <ckoenig.leichtzumerken@gmail.com>
To: "Ser, Simon" <simon.ser@intel.com>,
	"dri-devel@lists.freedesktop.org"
	<dri-devel@lists.freedesktop.org>,
	"alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>,
	"Kazlauskas, Nicholas" <Nicholas.Kazlauskas@amd.com>,
	"Wentland, Harry" <Harry.Wentland@amd.com>,
	"Leo (Sunpeng) Li" <sunpeng.li@amd.com>
Subject: Re: Linking ALSA playback devices and DRM connectors
Date: Tue, 4 Jun 2019 17:15:00 +0200	[thread overview]
Message-ID: <157c9015-32c8-2c1d-236f-48da16f43399@gmail.com> (raw)
In-Reply-To: <f69f48bd4b9b2dc6f8228cd47406882c71758cdf.camel@intel.com>

Am 04.06.19 um 17:05 schrieb Ser, Simon:
> Hi,
>
> I'm trying to link ALSA playback devices and DRM connectors. In other
> words, I'd like to be able to know which ALSA device I should open to
> play audio on a given connector.
>
> Unfortunately, I haven't found a way to extract this information. I
> know /proc/asound/cardN/eld* expose the EDID-like data. However by
> looking at the ALSA API (also: aplay -l and -L) I can't find a way to
> figure out which PCM device maps to the ELD.
>
> Am I missing something?

Is that actually fixed on all hardware? Or do we maybe have some 
hardware with only one audio codec and multiple connectors?

>
> If not, what would be the best way to expose this?
>
> - A symlink to the ALSA audio PCM device in
>    /sys/class/drm/cardN-CONNECTOR?
> - A symlink to the DRM connector in /sys/class/sound/pcm*?

If it's fixed than those two options sound sane to me.

> - A DRM connector property?

If it's configurable than that sounds like a good option to me.

Anyway added our DC team, stuff like that is their construction site.

Regards,
Christian.

> - Somehow expose the connector name via the ALSA API?
> - Expose the connector EDID via ALSA?
> - Other ideas?
>
> Thanks!
>
> Simon Ser
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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  reply	other threads:[~2019-06-04 15:15 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-04 15:05 Linking ALSA playback devices and DRM connectors Ser, Simon
2019-06-04 15:15 ` Christian König [this message]
2019-06-04 15:24   ` Daniel Vetter
2019-06-04 16:25     ` Ville Syrjälä
2019-06-11 10:01       ` [alsa-devel] " Takashi Iwai
2019-06-06  9:17     ` Ser, Simon
2019-06-06  9:13   ` Ser, Simon
2019-06-06  9:20     ` Koenig, Christian
2019-06-07 17:02     ` Ville Syrjälä

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