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

[Detlev Casanova <detlev.casanova@collabora.com>]

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.