[PATCH 0/3] Clean some logs on rockchip hdmi audio

[PATCH 0/3] Clean some logs on rockchip hdmi audio

[Detlev Casanova]

HDMI audio is showing lots of logs, particularly when HDMI is
disconnected.

It doubled on RK3588 with the addition of the second HDMI TX port, so
clean it up to avoid missing important log lines.

Detlev Casanova (3):
  drm/bridge: dw-hdmi-qp: Return 0 in audio prepare when disconnected
  ASoC: hdac_hdmi: Use dev_info on invalid ELD version
  drm/bridge: synopsys: Do not warn about audio params computation

 drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c | 5 ++---
 sound/soc/codecs/hdac_hdmi.c                 | 2 +-
 2 files changed, 3 insertions(+), 4 deletions(-)

-- 
2.50.1

[PATCH 1/3] drm/bridge: dw-hdmi-qp: Return 0 in audio prepare when disconnected

[Detlev Casanova]

To configure audio registers, the clock of the video port in use must be
enabled.
As those clocks are managed by the VOP driver, they can't be enabled here
to write the registers even when the HDMI cable is disconnected.

Furthermore, the registers values are computed from the TMDS char rate,
which is not available when disconnected.

Returning -ENODEV seemed reasonable at first, but ASoC will log an error
multiple times if dw_hdmi_qp_audio_prepare() return an error.
Userspace might also retry multiple times, filling the kernel log with:

hdmi-audio-codec hdmi-audio-codec.0.auto: ASoC error (-19): at snd_soc_dai_prepare() on i2s-hifi

This has become even worse with the support of the second HDMI TX port.

Activating the clocks to write fake data (fake because the TMDS char
rate is unavailable) would require API changes to communicate between
VOP and HDMI, which doesn't really make sense.

Using a cached regmap to be dumped when a cable is connected won't work
because writing order is important and some data needs to be retrieved
from registers to write others.

Returning 0 to silently fail sounds like the best and simplest solution.

Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
---
 drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
index 5e5f8c2f95be1..7d3d7b5084c8d 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
@@ -459,7 +459,7 @@ static int dw_hdmi_qp_audio_prepare(struct drm_connector *connector,
 	bool ref2stream = false;
 
 	if (!hdmi->tmds_char_rate)
-		return -ENODEV;
+		return 0;
 
 	if (fmt->bit_clk_provider | fmt->frame_clk_provider) {
 		dev_err(hdmi->dev, "unsupported clock settings\n");
-- 
2.50.1

Re: [PATCH 1/3] drm/bridge: dw-hdmi-qp: Return 0 in audio prepare when disconnected

[Heiko Stuebner]

Am Donnerstag, 17. Juli 2025, 23:56:18 Mitteleuropäische Sommerzeit schrieb Detlev Casanova:
> To configure audio registers, the clock of the video port in use must be
> enabled.
> As those clocks are managed by the VOP driver, they can't be enabled here
> to write the registers even when the HDMI cable is disconnected.
> 
> Furthermore, the registers values are computed from the TMDS char rate,
> which is not available when disconnected.
> 
> Returning -ENODEV seemed reasonable at first, but ASoC will log an error
> multiple times if dw_hdmi_qp_audio_prepare() return an error.
> Userspace might also retry multiple times, filling the kernel log with:
> 
> hdmi-audio-codec hdmi-audio-codec.0.auto: ASoC error (-19): at snd_soc_dai_prepare() on i2s-hifi
> 
> This has become even worse with the support of the second HDMI TX port.
> 
> Activating the clocks to write fake data (fake because the TMDS char
> rate is unavailable) would require API changes to communicate between
> VOP and HDMI, which doesn't really make sense.
> 
> Using a cached regmap to be dumped when a cable is connected won't work
> because writing order is important and some data needs to be retrieved
> from registers to write others.
> 
> Returning 0 to silently fail sounds like the best and simplest solution.
> 
> Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
> ---
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> index 5e5f8c2f95be1..7d3d7b5084c8d 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> @@ -459,7 +459,7 @@ static int dw_hdmi_qp_audio_prepare(struct drm_connector *connector,
>  	bool ref2stream = false;
>  
>  	if (!hdmi->tmds_char_rate)
> -		return -ENODEV;
> +		return 0;

nit: part of me would like a short comment stating the requirment of the
running video-clock.

Heiko

>  
>  	if (fmt->bit_clk_provider | fmt->frame_clk_provider) {
>  		dev_err(hdmi->dev, "unsupported clock settings\n");
> 

[PATCH 2/3] ASoC: hdac_hdmi: Use dev_info on invalid ELD version

[Detlev Casanova]

When disconnected, the ELD data cannot be read by the display driver, so
it just sets the data to 0.

That makes the ELD parsing code read an ELD version of 0, which is
invalid. In hdac_hdmi, that is logged with dev_err(), but should be
logged with dev_info() instead as it is done in sound/core/pcm_drm_eld.c

This avoids printing multiple messages like:

    HDMI: Unknown ELD version 0

in the kernel log when userspace tries to open the sound device.

Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
---
 sound/soc/codecs/hdac_hdmi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/codecs/hdac_hdmi.c b/sound/soc/codecs/hdac_hdmi.c
index 1139a2754ca33..4cc3b7a1062bd 100644
--- a/sound/soc/codecs/hdac_hdmi.c
+++ b/sound/soc/codecs/hdac_hdmi.c
@@ -1232,7 +1232,7 @@ static int hdac_hdmi_parse_eld(struct hdac_device *hdev,
 						>> DRM_ELD_VER_SHIFT;
 
 	if (ver != ELD_VER_CEA_861D && ver != ELD_VER_PARTIAL) {
-		dev_err(&hdev->dev, "HDMI: Unknown ELD version %d\n", ver);
+		dev_info(&hdev->dev, "HDMI: Unknown ELD version %d\n", ver);
 		return -EINVAL;
 	}
 
-- 
2.50.1

[PATCH 3/3] drm/bridge: synopsys: Do not warn about audio params computation

[Detlev Casanova]

There is no need to warn about non pre-computed values, just change it to
dbg.

Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
---
 drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
index 7d3d7b5084c8d..0571d604d8aa3 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
@@ -276,8 +276,7 @@ static unsigned int dw_hdmi_qp_find_n(struct dw_hdmi_qp *hdmi, unsigned long pix
 	if (n > 0)
 		return n;
 
-	dev_warn(hdmi->dev, "Rate %lu missing; compute N dynamically\n",
-		 pixel_clk);
+	dev_dbg(hdmi->dev, "Rate %lu missing; compute N dynamically\n", pixel_clk);
 
 	return dw_hdmi_qp_compute_n(hdmi, pixel_clk, sample_rate);
 }
-- 
2.50.1