Re: [linux-sunxi] Re: Audio sound card name [was [PATCH 4/7] arm64: dts: allwinner: a64: Add HDMI audio]
From: Robin Murphy
Date: Wed Apr 29 2020 - 07:08:09 EST
On 2020-04-29 11:53 am, Jernej Åkrabec wrote:
Dne sreda, 29. april 2020 ob 12:43:06 CEST je Robin Murphy napisal(a):
On 2020-04-29 9:17 am, Maxime Ripard wrote:
On Wed, Apr 29, 2020 at 02:24:00PM +0800, Chen-Yu Tsai wrote:
On Wed, Apr 29, 2020 at 1:11 AM Robin Murphy <robin.murphy@xxxxxxx>
wrote:
On 2020-04-28 5:49 pm, ClÃment PÃron wrote:
Hi Mark, Rob,
On Tue, 28 Apr 2020 at 18:04, Maxime Ripard <maxime@xxxxxxxxxx> wrote:
On Tue, Apr 28, 2020 at 10:54:00AM +0200, ClÃment PÃron wrote:
Hi Maxime,
On Tue, 28 Apr 2020 at 10:00, Maxime Ripard <maxime@xxxxxxxxxx>
wrote:
On Sun, Apr 26, 2020 at 02:04:39PM +0200, ClÃment PÃron wrote:
From: Marcus Cooper <codekipper@xxxxxxxxx>
Add a simple-soundcard to link audio between HDMI and I2S.
Signed-off-by: Jernej Skrabec <jernej.skrabec@xxxxxxxx>
Signed-off-by: Marcus Cooper <codekipper@xxxxxxxxx>
Signed-off-by: ClÃment PÃron <peron.clem@xxxxxxxxx>
---
arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi | 21
+++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi index
e56e1e3d4b73..08ab6b5e72a5 100644
--- a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
+++ b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
@@ -102,6 +102,25 @@
status = "disabled";
};
+ hdmi_sound: hdmi-sound {
+ compatible = "simple-audio-card";
+ simple-audio-card,format = "i2s";
+ simple-audio-card,name = "allwinner,hdmi";
I'm not sure what the usual card name should be like though. I would
assume that this should be something specific enough so that you're
able to differentiate between boards / SoC so that the userspace
can choose a different configuration based on it?
I really don't know what we should use here,
I just have a look at other SoC:
rk3328: "HDMI"
rk3399: "hdmi-sound"
r8a774c0-cat874: "CAT874 HDMI sound"
But maybe it's time to introduce proper name:
What about :
pat
sun50i-h6-hdmi
It's pretty much what we've been using for the other sound cards we
have, so it makes sense to me.
I have a question regarding the simple-audio-card,name.
In this patch, I would like to introduce a simple-audio-card for the
Allwinner A64 HDMI.
What should be the preferred name for this sound card?
"sun50i-a64-hdmi" ? "allwinner, sun50i-a64-hdmi" ?
I can at least speak for RK3328, and the reasoning there was that as the
user looking at what `aplay -l` says, I don't give a hoot about what the
SoC may be called, I see two cards and I want to know, with the least
amount of uncertainty, which one will make the sound come out of the
port that's labelled "HDMI" on the box ;)
I agree. The user really doesn't care what SoC the system uses. The only
real requirement is to be able to tell which output the card is related
to, i.e. is it onboard or an external DAC, is it analog or HDMI, etc..
Yeah, but it's exactly the point.
If we also end up with "HDMI" as our card name, then the userspace has no
way to tell anymore if it's running from an rk3328 or an allwinner SoC,
or something else entirely. And therefore it cannot really configure
anything to work out of the box anymore.
OK, you're a userspace audio application - enlighten me as to what exact
chip you're running on here, and why you need to know:
card 0: HDMI [HDA ATI HDMI]
or how about here?
card 0: Intel [HDA Intel]
Furthermore, your argument works both ways - if the equivalent (or in
common cases like DesignWare IP blocks, exact same) thing across 3
different SoCs has 3 different names, then it's that much harder for
userspace that wants to present a consistent behaviour. I don't know
exactly why LibreELEC have downstream patches that standardise all the
Rockchip ones to "HDMI", but I can't help noting that they do.
With simple-audio-card we're talking about trivial interfaces that often
don't expose any controls at all, so there's unlikely to be much
'configuration' for userspace to do beyond choosing which card to output to.
This combination (DesignWare HDMI controller + I2S) is same as on Rockchip.
Only difference is slightly different version of HDMI controller and different
I2S core. Not sure what kind of configuration do you have in mind, but all
these controllers support 2-8 channels, different sample sizes, even
passthrough mode can be set (but it's not implemented yet). I would say that
this audio output supports quiet a few possible configurations.
Right, what I'm getting at is that the stuff that matters is all regular
audio capabilities exposed via the appropriate APIs, and any choices are
going to be mostly based on the audio being played and what the receiver
on the other end of the link supports. I'm genuinely curious as to what
actual configuration decision could be made purely based on the SoC
name, regardless of the board, receiver, or the capabilities advertised
by the interface itself.
Thanks,
Robin.