[PATCH] drm/bridge: dw-hdmi-qp: Return -EOPNOTSUPP in HDMI audio functions

[PATCH] drm/bridge: dw-hdmi-qp: Return -EOPNOTSUPP in HDMI audio functions

[Detlev Casanova]

-EOPNOTSUPP is not logged as an error by the ASoC subsystem, but -ENODEV
is.
It also better represents the situation: The operation is currently not
supported (because clocks are not enabled and tmds_char_rate is
unavailable), but the hardware is present.

Using -EOPNOTSUPP in the audio_prepare callback removes possible repeated
warning log lines when HDMI is not connected.

Returning -EOPNOTSUPP in the audio_enable callback is also needed as it
avoids logging 0-valued ELD errors.

When tmds_char_rate is available, the clocks are enabled and the
functions will keep returning 0 as before.

Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
---
 drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
index d649a1cf07f5..270c8c47d853 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
@@ -469,8 +469,10 @@ static int dw_hdmi_qp_audio_enable(struct drm_bridge *bridge,
 {
 	struct dw_hdmi_qp *hdmi = dw_hdmi_qp_from_bridge(bridge);
 
-	if (hdmi->tmds_char_rate)
-		dw_hdmi_qp_mod(hdmi, 0, AVP_DATAPATH_PACKET_AUDIO_SWDISABLE, GLOBAL_SWDISABLE);
+	if (!hdmi->tmds_char_rate)
+		return -EOPNOTSUPP;
+
+	dw_hdmi_qp_mod(hdmi, 0, AVP_DATAPATH_PACKET_AUDIO_SWDISABLE, GLOBAL_SWDISABLE);
 
 	return 0;
 }
@@ -484,7 +486,7 @@ static int dw_hdmi_qp_audio_prepare(struct drm_bridge *bridge,
 	bool ref2stream = false;
 
 	if (!hdmi->tmds_char_rate)
-		return -ENODEV;
+		return -EOPNOTSUPP;
 
 	if (fmt->bit_clk_provider | fmt->frame_clk_provider) {
 		dev_err(hdmi->dev, "unsupported clock settings\n");

---
base-commit: 1a2ab0feaa23147e347b4d4cb79cb3fc392118eb
change-id: 20260519-fix-hdmi-audio-warnings-139062ec00b9

Best regards,
--  
Detlev Casanova <detlev.casanova@collabora.com>

Re: [PATCH] drm/bridge: dw-hdmi-qp: Return -EOPNOTSUPP in HDMI audio functions

[Sebastian Reichel]

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Hello Detlev,

On Tue, May 19, 2026 at 02:00:11PM -0400, Detlev Casanova wrote:
> -EOPNOTSUPP is not logged as an error by the ASoC subsystem, but -ENODEV
> is.
> It also better represents the situation: The operation is currently not
> supported (because clocks are not enabled and tmds_char_rate is
> unavailable), but the hardware is present.
> 
> Using -EOPNOTSUPP in the audio_prepare callback removes possible repeated
> warning log lines when HDMI is not connected.
> 
> Returning -EOPNOTSUPP in the audio_enable callback is also needed as it
> avoids logging 0-valued ELD errors.
> 
> When tmds_char_rate is available, the clocks are enabled and the
> functions will keep returning 0 as before.
> 
> Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>

Fixes: fd0141d1a8a2a ("drm/bridge: synopsys: Add audio support for dw-hdmi-qp")

Greetings,

-- Sebastian

> ---
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> index d649a1cf07f5..270c8c47d853 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> @@ -469,8 +469,10 @@ static int dw_hdmi_qp_audio_enable(struct drm_bridge *bridge,
>  {
>  	struct dw_hdmi_qp *hdmi = dw_hdmi_qp_from_bridge(bridge);
>  
> -	if (hdmi->tmds_char_rate)
> -		dw_hdmi_qp_mod(hdmi, 0, AVP_DATAPATH_PACKET_AUDIO_SWDISABLE, GLOBAL_SWDISABLE);
> +	if (!hdmi->tmds_char_rate)
> +		return -EOPNOTSUPP;
> +
> +	dw_hdmi_qp_mod(hdmi, 0, AVP_DATAPATH_PACKET_AUDIO_SWDISABLE, GLOBAL_SWDISABLE);
>  
>  	return 0;
>  }
> @@ -484,7 +486,7 @@ static int dw_hdmi_qp_audio_prepare(struct drm_bridge *bridge,
>  	bool ref2stream = false;
>  
>  	if (!hdmi->tmds_char_rate)
> -		return -ENODEV;
> +		return -EOPNOTSUPP;
>  
>  	if (fmt->bit_clk_provider | fmt->frame_clk_provider) {
>  		dev_err(hdmi->dev, "unsupported clock settings\n");
> 
> ---
> base-commit: 1a2ab0feaa23147e347b4d4cb79cb3fc392118eb
> change-id: 20260519-fix-hdmi-audio-warnings-139062ec00b9
> 
> Best regards,
> --  
> Detlev Casanova <detlev.casanova@collabora.com>
> 

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Re: [PATCH] drm/bridge: dw-hdmi-qp: Return -EOPNOTSUPP in HDMI audio functions

[Maud Spierings]

> -EOPNOTSUPP is not logged as an error by the ASoC subsystem, but -ENODEV
> is.
> It also better represents the situation: The operation is currently not
> supported (because clocks are not enabled and tmds_char_rate is
> unavailable), but the hardware is present.
> 
> Using -EOPNOTSUPP in the audio_prepare callback removes possible repeated
> warning log lines when HDMI is not connected.
> 
> Returning -EOPNOTSUPP in the audio_enable callback is also needed as it
> avoids logging 0-valued ELD errors.
> 
> When tmds_char_rate is available, the clocks are enabled and the
> functions will keep returning 0 as before.
> 
> Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>

Error messages are gone, tested on Orangepi 5+

Kind regards,
Maud

Tested-by: Maud Spierings <maud_spierings@hotmail.com>

> ---
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> index d649a1cf07f5..270c8c47d853 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> @@ -469,8 +469,10 @@ static int dw_hdmi_qp_audio_enable(struct drm_bridge *bridge,
>  {
>  	struct dw_hdmi_qp *hdmi = dw_hdmi_qp_from_bridge(bridge);
>  
> -	if (hdmi->tmds_char_rate)
> -		dw_hdmi_qp_mod(hdmi, 0, AVP_DATAPATH_PACKET_AUDIO_SWDISABLE, GLOBAL_SWDISABLE);
> +	if (!hdmi->tmds_char_rate)
> +		return -EOPNOTSUPP;
> +
> +	dw_hdmi_qp_mod(hdmi, 0, AVP_DATAPATH_PACKET_AUDIO_SWDISABLE, GLOBAL_SWDISABLE);
>  
>  	return 0;
>  }
> @@ -484,7 +486,7 @@ static int dw_hdmi_qp_audio_prepare(struct drm_bridge *bridge,
>  	bool ref2stream = false;
>  
>  	if (!hdmi->tmds_char_rate)
> -		return -ENODEV;
> +		return -EOPNOTSUPP;
>  
>  	if (fmt->bit_clk_provider | fmt->frame_clk_provider) {
>  		dev_err(hdmi->dev, "unsupported clock settings\n");
> 
> ---
> base-commit: 1a2ab0feaa23147e347b4d4cb79cb3fc392118eb
> change-id: 20260519-fix-hdmi-audio-warnings-139062ec00b9
> 
> Best regards,
> --  
> Detlev Casanova <detlev.casanova@collabora.com>

Re: [PATCH] drm/bridge: dw-hdmi-qp: Return -EOPNOTSUPP in HDMI audio functions

[Detlev Casanova]

Hi all,

On Tuesday, 19 May 2026 14:00:11 EDT Detlev Casanova wrote:
> -EOPNOTSUPP is not logged as an error by the ASoC subsystem, but -ENODEV
> is.
> It also better represents the situation: The operation is currently not
> supported (because clocks are not enabled and tmds_char_rate is
> unavailable), but the hardware is present.
> 
> Using -EOPNOTSUPP in the audio_prepare callback removes possible repeated
> warning log lines when HDMI is not connected.
> 
> Returning -EOPNOTSUPP in the audio_enable callback is also needed as it
> avoids logging 0-valued ELD errors.
> 
> When tmds_char_rate is available, the clocks are enabled and the
> functions will keep returning 0 as before.
> 
> Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>

Gentle nudge on this one.

> ---
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c index
> d649a1cf07f5..270c8c47d853 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> @@ -469,8 +469,10 @@ static int dw_hdmi_qp_audio_enable(struct drm_bridge
> *bridge, {
>  	struct dw_hdmi_qp *hdmi = dw_hdmi_qp_from_bridge(bridge);
> 
> -	if (hdmi->tmds_char_rate)
> -		dw_hdmi_qp_mod(hdmi, 0, 
AVP_DATAPATH_PACKET_AUDIO_SWDISABLE,
> GLOBAL_SWDISABLE); +	if (!hdmi->tmds_char_rate)
> +		return -EOPNOTSUPP;
> +
> +	dw_hdmi_qp_mod(hdmi, 0, AVP_DATAPATH_PACKET_AUDIO_SWDISABLE,
> GLOBAL_SWDISABLE);
> 
>  	return 0;
>  }
> @@ -484,7 +486,7 @@ static int dw_hdmi_qp_audio_prepare(struct drm_bridge
> *bridge, bool ref2stream = false;
> 
>  	if (!hdmi->tmds_char_rate)
> -		return -ENODEV;
> +		return -EOPNOTSUPP;
> 
>  	if (fmt->bit_clk_provider | fmt->frame_clk_provider) {
>  		dev_err(hdmi->dev, "unsupported clock settings\n");
> 
> ---
> base-commit: 1a2ab0feaa23147e347b4d4cb79cb3fc392118eb
> change-id: 20260519-fix-hdmi-audio-warnings-139062ec00b9
> 
> Best regards,
> --
> Detlev Casanova <detlev.casanova@collabora.com>

Re: [PATCH] drm/bridge: dw-hdmi-qp: Return -EOPNOTSUPP in HDMI audio functions

[Diederik de Haas]

Hi Detlev,

On Tue May 19, 2026 at 8:00 PM CEST, Detlev Casanova wrote:
> -EOPNOTSUPP is not logged as an error by the ASoC subsystem, but -ENODEV
> is.
> It also better represents the situation: The operation is currently not
> supported (because clocks are not enabled and tmds_char_rate is
> unavailable), but the hardware is present.
>
> Using -EOPNOTSUPP in the audio_prepare callback removes possible repeated
> warning log lines when HDMI is not connected.

IME/IMO that's a bit of an understatement as I got 10/100/1000s of these:

  hdmi-audio-codec hdmi-audio-codec.6.auto: ASoC error (-19): at snd_soc_dai_prepare() on i2s-hifi

In my test without this patch, I booted up my SBCs, logged in quickly and
still got 60/120/270 of these errors in dmesg ... and I wasn't actually 
using HDMI at that time. Previously, more then once did it completely
fill the dmesg buffer, removing/hiding the things I actually wanted to see.

> Returning -EOPNOTSUPP in the audio_enable callback is also needed as it
> avoids logging 0-valued ELD errors.

I've seen those too, multiple times, although it didn't annoy me as much
as the above one ... due to the (much) lower frequency. So

1) Thanks a LOT for this patch :-D
2) Feel free to include my

Tested-by: Diederik de Haas <diederik@cknow-tech.com>  # Rock 5B, NanoPC-T6 LTS & Plus

Cheers,
  Diederik

> When tmds_char_rate is available, the clocks are enabled and the
> functions will keep returning 0 as before.
>
> Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
> ---
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> index d649a1cf07f5..270c8c47d853 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> @@ -469,8 +469,10 @@ static int dw_hdmi_qp_audio_enable(struct drm_bridge *bridge,
>  {
>  	struct dw_hdmi_qp *hdmi = dw_hdmi_qp_from_bridge(bridge);
>  
> -	if (hdmi->tmds_char_rate)
> -		dw_hdmi_qp_mod(hdmi, 0, AVP_DATAPATH_PACKET_AUDIO_SWDISABLE, GLOBAL_SWDISABLE);
> +	if (!hdmi->tmds_char_rate)
> +		return -EOPNOTSUPP;
> +
> +	dw_hdmi_qp_mod(hdmi, 0, AVP_DATAPATH_PACKET_AUDIO_SWDISABLE, GLOBAL_SWDISABLE);
>  
>  	return 0;
>  }
> @@ -484,7 +486,7 @@ static int dw_hdmi_qp_audio_prepare(struct drm_bridge *bridge,
>  	bool ref2stream = false;
>  
>  	if (!hdmi->tmds_char_rate)
> -		return -ENODEV;
> +		return -EOPNOTSUPP;
>  
>  	if (fmt->bit_clk_provider | fmt->frame_clk_provider) {
>  		dev_err(hdmi->dev, "unsupported clock settings\n");
>
> ---
> base-commit: 1a2ab0feaa23147e347b4d4cb79cb3fc392118eb
> change-id: 20260519-fix-hdmi-audio-warnings-139062ec00b9
>
> Best regards,
> --  
> Detlev Casanova <detlev.casanova@collabora.com>

Re: [PATCH] drm/bridge: dw-hdmi-qp: Return -EOPNOTSUPP in HDMI audio functions

[Maud Spierings]

Hi everyone,

Another month, another reminder.
Or is there some reason why this isn't getting picked up?

kind regards,
Maud

Re: [PATCH] drm/bridge: dw-hdmi-qp: Return -EOPNOTSUPP in HDMI audio functions

[Igor Paunovic]

Hi Detlev,

One more data point for this one, from an Orange Pi 5 Plus (RK3588).

Without the patch, every prepare on an HDMI PCM whose output is not lit
(tmds_char_rate == 0: early in boot before the compositor enables the
output, or with the output disabled in the compositor) logs

  hdmi-audio-codec hdmi-audio-codec.N.auto: ASoC error (-19): at snd_soc_dai_prepare() on i2s-hifi

On two boots here with the link perfectly fine that was 115 and 114 lines,
in two bursts each (60 and 55 prepares ~1 ms apart at 15.7 s and 28.1 s
after boot on one, 60 and 54 at 14.8 s and 22.0 s on the other) - as far
as I can tell PipeWire probing the cards from the greeter session before
the compositor had lit the outputs. On the boot just before those two,
where the sink had also failed SCDC, there were four of them and then the
SError described in [2].

Disabling one output in the compositor and opening its PCM reproduces
it on demand: exactly one line per prepare - and, on the close that
follows, the abort in clear_audio_infoframe() described in [2].

With the patch applied (rebuilt dw_hdmi_qp module, same kernel), opening
the PCM of an output disabled in the compositor now fails right away in
hdmi_codec_startup() with EOPNOTSUPP - nothing from ASoC or the bridge
in the kernel log, aplay says "Operation not supported" - and audio on
the output that has a link works as before.

Tested-by: Igor Paunovic <royalnet026@gmail.com> # Orange Pi 5 Plus

One more reason I think this and Frank Zhang's patch [1] belong together:
since the startup now fails, ASoC never marks the DAI as started, so for
a PCM opened on a dead link the close never reaches hdmi_codec_shutdown()
-> dw_hdmi_qp_audio_disable() -> clear_audio_infoframe(). That is the
same class of bug as the SError we hit here on 02.09 (PCM closed after a
failed prepare, register access with the PHY down -> SError, panic; full
trace in [2]). I can't be certain this patch alone would have prevented
that particular crash - a PCM that is already open when the output goes
down still walks that path, which is what Frank's guard is for - so both
still look needed to me. (I saw Cristian's question on v4 about
open-coding the clear; either shape works for the crash I hit.)

[1] https://lore.kernel.org/all/20260512103153.8861-1-rmxpzlb@gmail.com/
[2] https://lore.kernel.org/all/20260907153000.hdmiqp-audio-1-royalnet026@gmail.com/

Thanks,
Igor

Re: [PATCH] drm/bridge: dw-hdmi-qp: Return -EOPNOTSUPP in HDMI audio functions

[Detlev Casanova]

Hi Igor,

Thank you for testing !

On Monday, 7 September 2026 09:01:30 EDT Igor Paunovic wrote:
> Hi Detlev,
> 
[...]
> 
> One more reason I think this and Frank Zhang's patch [1] belong together:
> since the startup now fails, ASoC never marks the DAI as started, so for
> a PCM opened on a dead link the close never reaches hdmi_codec_shutdown()
> -> dw_hdmi_qp_audio_disable() -> clear_audio_infoframe(). That is the
> same class of bug as the SError we hit here on 02.09 (PCM closed after a
> failed prepare, register access with the PHY down -> SError, panic; full
> trace in [2]). I can't be certain this patch alone would have prevented
> that particular crash - a PCM that is already open when the output goes
> down still walks that path, which is what Frank's guard is for - so both
> still look needed to me. (I saw Cristian's question on v4 about
> open-coding the clear; either shape works for the crash I hit.)

Yes, Frank's patch is still needed, this is not fixing the SError, only giving 
asoc and userspace the right error code.

The situation you describe on opened PCM that goes down can indeed still 
happen (This patch may just decrease the probability of seeing an SError)

> [1] https://lore.kernel.org/all/20260512103153.8861-1-rmxpzlb@gmail.com/
> [2]
> https://lore.kernel.org/all/20260907153000.hdmiqp-audio-1-royalnet026@gmail
> .com/

Detlev.