Re: [PATCH v3] drm/amdgpu: Only enable HDMI audio if display supports it

["Timur Kristóf" <timur.kristof@gmail.com>]

On Tue, 2026-11-03 at 14:11 +0800, Panpan Ren wrote:
> From: renpanpan <renpanpan@kylinos.cn>
> 
> The amdgpu legacy DCE audio path (dce_v6/v8/v10) unconditionally
> calls
> audio_enable(pin, true) at the end of afmt_setmode(), regardless of
> whether the connected display advertises audio support in its EDID.
> 
> This causes a phantom HDMI audio output to appear for displays that
> have no audio capability (no basic audio bit, no Audio Data Block in
> EDID), because the GPU sets the AUDIO_ENABLED register bit, which
> drives the HDA codec's ELDV pin sense, making the codec report the
> jack as audio-available.
> 
> The radeon, nouveau, and dw-hdmi drivers all gate audio enablement on
> the display's audio capability. Apply the same check to amdgpu's DCE
> afmt_setmode functions, while still respecting the
> AMDGPU_AUDIO_ENABLE
> override for users who explicitly force audio on.
> 
> Fixes: e2cdf640cbb5 ("drm/amdgpu: add display controller
> implementation for si v10")
> Cc: stable@vger.kernel.org
> Signed-off-by: renpanpan <renpanpan@kylinos.cn>

Makes sense, thank you!

Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>


> ---
> Changes in v3:
> - Also gate the initial audio_enable(pin, false) to avoid touching a
>   potentially shared audio pin when the display has no audio support
> 
> Changes in v2:
> - Respect AMDGPU_AUDIO_ENABLE override for users who force audio on
> - Add Fixes tag and Cc: stable@vger.kernel.org for stable backport
> 
>  drivers/gpu/drm/amd/amdgpu/dce_v10_0.c | 12 ++++++++----
>  drivers/gpu/drm/amd/amdgpu/dce_v6_0.c  | 12 ++++++++----
>  drivers/gpu/drm/amd/amdgpu/dce_v8_0.c  | 12 ++++++++----
>  3 files changed, 24 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
> b/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
> index f2977fe6d824..a8f5eb2394c6 100644
> --- a/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
> @@ -1555,9 +1555,11 @@ static void dce_v10_0_afmt_setmode(struct
> drm_encoder *encoder,
>  		bpc = amdgpu_crtc->bpc;
>  	}
>  
> -	/* disable audio prior to setting up hw */
> +	/* disable audio prior to setting up hw, unless the display
> has no audio */
>  	dig->afmt->pin = dce_v10_0_audio_get_pin(adev);
> -	dce_v10_0_audio_enable(adev, dig->afmt->pin, false);
> +	if (connector->display_info.has_audio ||
> +	    to_amdgpu_connector(connector)->audio ==
> AMDGPU_AUDIO_ENABLE)
> +		dce_v10_0_audio_enable(adev, dig->afmt->pin, false);
>  
>  	dce_v10_0_audio_set_dto(encoder, mode->clock);
>  
> @@ -1705,8 +1707,10 @@ static void dce_v10_0_afmt_setmode(struct
> drm_encoder *encoder,
>  	WREG32(mmAFMT_RAMP_CONTROL2 + dig->afmt->offset,
> 0x00000001);
>  	WREG32(mmAFMT_RAMP_CONTROL3 + dig->afmt->offset,
> 0x00000001);
>  
> -	/* enable audio after to setting up hw */
> -	dce_v10_0_audio_enable(adev, dig->afmt->pin, true);
> +	/* Only enable audio if the display supports it or is forced
> on */
> +	if (connector->display_info.has_audio ||
> +	    to_amdgpu_connector(connector)->audio ==
> AMDGPU_AUDIO_ENABLE)
> +		dce_v10_0_audio_enable(adev, dig->afmt->pin, true);
>  }
>  
>  static void dce_v10_0_afmt_enable(struct drm_encoder *encoder, bool
> enable)
> diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c
> b/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c
> index c68de0fe1d7d..3cd9f1bb3a70 100644
> --- a/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c
> @@ -1724,8 +1724,10 @@ static void dce_v6_0_afmt_setmode(struct
> drm_encoder *encoder,
>  		bpc = amdgpu_crtc->bpc;
>  	}
>  
> -	/* disable audio before setting up hw */
> -	dce_v6_0_audio_enable(adev, dig->afmt->pin, false);
> +	/* disable audio before setting up hw, unless the display
> has no audio */
> +	if (connector->display_info.has_audio ||
> +	    amdgpu_connector->audio == AMDGPU_AUDIO_ENABLE)
> +		dce_v6_0_audio_enable(adev, dig->afmt->pin, false);
>  
>  	dce_v6_0_audio_set_mute(encoder, true);
>  	dce_v6_0_audio_write_speaker_allocation(encoder);
> @@ -1748,8 +1750,10 @@ static void dce_v6_0_afmt_setmode(struct
> drm_encoder *encoder,
>  		dce_v6_0_audio_dp_enable(encoder, 1);
>  	}
>  
> -	/* enable audio after setting up hw */
> -	dce_v6_0_audio_enable(adev, dig->afmt->pin, true);
> +	/* Only enable audio if the display supports it or is forced
> on */
> +	if (connector->display_info.has_audio ||
> +	    amdgpu_connector->audio == AMDGPU_AUDIO_ENABLE)
> +		dce_v6_0_audio_enable(adev, dig->afmt->pin, true);
>  }
>  
>  static void dce_v6_0_afmt_enable(struct drm_encoder *encoder, bool
> enable)
> diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c
> b/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c
> index c3906270f25e..eb1fcf0b39cc 100644
> --- a/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c
> @@ -1523,9 +1523,11 @@ static void dce_v8_0_afmt_setmode(struct
> drm_encoder *encoder,
>  		bpc = amdgpu_crtc->bpc;
>  	}
>  
> -	/* disable audio prior to setting up hw */
> +	/* disable audio prior to setting up hw, unless the display
> has no audio */
>  	dig->afmt->pin = dce_v8_0_audio_get_pin(adev);
> -	dce_v8_0_audio_enable(adev, dig->afmt->pin, false);
> +	if (connector->display_info.has_audio ||
> +	    to_amdgpu_connector(connector)->audio ==
> AMDGPU_AUDIO_ENABLE)
> +		dce_v8_0_audio_enable(adev, dig->afmt->pin, false);
>  
>  	dce_v8_0_audio_set_dto(encoder, mode->clock);
>  
> @@ -1653,8 +1655,10 @@ static void dce_v8_0_afmt_setmode(struct
> drm_encoder *encoder,
>  	WREG32(mmAFMT_RAMP_CONTROL2 + offset, 0x00000001);
>  	WREG32(mmAFMT_RAMP_CONTROL3 + offset, 0x00000001);
>  
> -	/* enable audio after setting up hw */
> -	dce_v8_0_audio_enable(adev, dig->afmt->pin, true);
> +	/* Only enable audio if the display supports it or is forced
> on */
> +	if (connector->display_info.has_audio ||
> +	    to_amdgpu_connector(connector)->audio ==
> AMDGPU_AUDIO_ENABLE)
> +		dce_v8_0_audio_enable(adev, dig->afmt->pin, true);
>  }
>  
>  static void dce_v8_0_afmt_enable(struct drm_encoder *encoder, bool
> enable)