Re: [PATCH v2] drm/bridge: dw-hdmi-qp: Guard clear_audio_infoframe when PHY is down

[Dmitry Baryshkov]

On Sat, Apr 18, 2026 at 06:19:36PM +0800, Frank Zhang wrote:
> The following panic was observed during system reboot:
> 
> Kernel panic - not syncing: Asynchronous SError Interrupt
> CPU: 7 UID: 1000 PID: 2637 Comm: pipewire ... 6.19.10-300.fc44.aarch64
> Call trace:
>  ...
>  regmap_update_bits_base+0x5c/0x90
>  dw_hdmi_qp_bridge_clear_infoframe+0xb0/0x120 [dw_hdmi_qp]
>  drm_bridge_connector_clear_infoframe+0x28/0x48 [drm_display_helper]
>  ...
>  dw_hdmi_qp_audio_disable+0x24/0xb8 [dw_hdmi_qp]
>  drm_bridge_connector_audio_shutdown+0x30/0x60 [drm_display_helper]
>  drm_connector_hdmi_audio_shutdown+0x24/0x38 [drm_display_helper]
>  hdmi_codec_shutdown+0x60/0x90 [snd_soc_hdmi_codec]
>  ...
>  snd_pcm_release_substream.part.0+0x44/0xd8 [snd_pcm]
>  snd_pcm_release+0x60/0xe8 [snd_pcm]
>  ...
> 
> The root cause is pipewire tries to close the HDMI audio device after
> atomic_disable(), which sets tmds_char_rate to 0 and disable the PHY.
> 
> In this case, dw_hdmi_qp_audio_disable() will call
> drm_atomic_helper_connector_hdmi_clear_audio_infoframe() directly,
> accessing registers without checking tmds_char_rate.
> 
> Move drm_atomic_helper_connector_hdmi_clear_audio_infoframe() inside the
> if (hdmi->tmds_char_rate) of dw_hdmi_qp_audio_disable().
> 
> Fixes: fd0141d1a8a2 ("drm/bridge: synopsys: Add audio support for dw-hdmi-qp")
> Signed-off-by: Frank Zhang <rmxpzlb@xxxxxxxxx>
> 
> ---
> Changes in v2:
> - Move drm_atomic_helper_connector_hdmi_clear_audio_infoframe() inside
>   the if (hdmi->tmds_char_rate) of dw_hdmi_qp_audio_disable().
> - Link to v1: https://lore.kernel.org/all/20260416093150.13853-1-rmxpzlb@xxxxxxxxx/
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> index d649a1cf07f5..7760527484c8 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> @@ -526,10 +526,10 @@ static void dw_hdmi_qp_audio_disable(struct drm_bridge *bridge,
>  {
>  	struct dw_hdmi_qp *hdmi = dw_hdmi_qp_from_bridge(bridge);
>  
> -	drm_atomic_helper_connector_hdmi_clear_audio_infoframe(connector);
> -
> -	if (hdmi->tmds_char_rate)
> +	if (hdmi->tmds_char_rate) {
> +		drm_atomic_helper_connector_hdmi_clear_audio_infoframe(connector);
>  		dw_hdmi_qp_audio_disable_regs(hdmi);
> +	}

Will audio and audio infoframe remain disabled after consequetive
atomic_enable() call?

>  }
>  
>  static int dw_hdmi_qp_i2c_read(struct dw_hdmi_qp *hdmi,
> -- 
> 2.53.0
> 

-- 
With best wishes
Dmitry