[PATCH v10 03/10] drm/connector: implement generic HDMI audio helpers

[Martin Blumenstingl]

On Tue, Dec 31, 2024 at 3:34 AM Dmitry Baryshkov
<dmitry.baryshkov at linaro.org> wrote:
[...]
> > I checked all instances of struct hdmi_codec_ops in v6.13-rc3 and it
> > seems that there is only a single driver which uses the .prepare
> > callback (drivers/gpu/drm/vc4/vc4_hdmi.c). All other drivers seem to
> > implement .hw_params instead.
>
> Yes. However .hw_params don't have access to the infoframe contents, so
> I had to settle on implementing .prepare.
While debugging I noticed something unrelated to my problem:
hdmi_codec_spdif_dai_ops does not implement .prepare().
FYI just in case someone wants to use your patches and feed the
hdmi-codec with SPDIF instead of I2S.

> >
> > The audio controller code for my platform is already upstream:
> > - sound/soc/meson/aiu-codec-ctrl.c
> > - sound/soc/meson/aiu-encoder-i2s.c
> > - sound/soc/meson/aiu-fifo-i2s.c
> >
> > My understanding is that you have a platform with a lontium-lt9611
> > HDMI controller available for testing. Can you please help me
> > investigate and find out which piece of code is calling
> > hdmi_codec_prepare() and therefore lt9611_hdmi_audio_prepare() on
> > your board?
>
> Sure, this is the call trace on my platform (Qualcomm SDM845,
> sdm845-db845c.dts):
>
> lt9611_hdmi_audio_prepare+0x1c/0xc0 (P)
> drm_bridge_connector_audio_prepare+0x2c/0x40 (L)
> drm_bridge_connector_audio_prepare+0x2c/0x40
> drm_connector_hdmi_audio_prepare+0x24/0x30
> hdmi_codec_prepare+0xec/0x144
> snd_soc_pcm_dai_prepare+0x78/0x10c
Thank you, this helps! snd_soc_pcm_dai_prepare() is where it breaks for me.
I suspect that it's an sound card issue on our platform, so I'm hoping
that Jerome (author of the Amlogic ASoC drivers) will help me debug
it: [0]


Best regards,
Martin


[0] https://lore.kernel.org/linux-amlogic/CAFBinCDdiJ3UNVUcShjq=7U2=oUwT3ciYdKSuZ5TdcrikxFBpg@mail.gmail.com/