Re: [PATCH v2 2/4] ASoC: codecs: hda: Skip HDMI/DP registration if i915 is missing

[Takashi Iwai <tiwai@xxxxxxx>]

On Fri, 23 Feb 2024 18:09:59 +0100,
Cezary Rojewski wrote:
> 
> On 2024-02-23 3:44 PM, Takashi Iwai wrote:
> > On Fri, 23 Feb 2024 12:46:24 +0100,
> > Cezary Rojewski wrote:
> >> 
> >> If i915 does not support given platform but the hardware i.e.: HDAudio
> >> codec is still there, the codec-probing procedure will succeed for such
> >> device but the follow up initialization will always end up with -ENODEV.
> >> 
> >> While bus could filter out address '2' which Intel's HDMI/DP codecs
> >> always enumerate on, more robust approach is to check for i915 presence
> >> before registering display codecs.
> >> 
> >> Signed-off-by: Cezary Rojewski <cezary.rojewski@xxxxxxxxx>
> >> ---
> >>   sound/soc/codecs/hda.c | 5 +++++
> >>   1 file changed, 5 insertions(+)
> >> 
> >> diff --git a/sound/soc/codecs/hda.c b/sound/soc/codecs/hda.c
> >> index d2117e36ddd1..d9e7cd8aada2 100644
> >> --- a/sound/soc/codecs/hda.c
> >> +++ b/sound/soc/codecs/hda.c
> >> @@ -350,6 +350,11 @@ static int hda_hdev_attach(struct hdac_device *hdev)
> >>   	struct hda_codec *codec = dev_to_hda_codec(&hdev->dev);
> >>   	struct snd_soc_component_driver *comp_drv;
> >>   +	if (hda_codec_is_display(codec) &&
> >> !hdev->bus->audio_component) {
> >> +		dev_dbg(&hdev->dev, "no i915, skip registration for 0x%08x\n", hdev->vendor_id);
> >> +		return 0;
> > 
> > Should we return success here, or would it better with -ENODEV?
> > IIUC, the code path is from the early hda_codec_driver_probe() hook,
> > so returning an error can work.
> 
> Good suggestion. Indeed attach() is called by probe() which treats
> -ENODEV just fine.
> 
> There is a consequence to that though. Logs from LKF show:
> 
> snd_soc_hda_codec:hda_hdev_attach: snd_hda_codec_hdmi hdaudioB0D2: no
> i915, skip registration for 0x80862811
> snd_soc_hda_codec:hda_hdev_attach: snd_hda_codec_generic hdaudioB0D2:
> no i915, skip registration for 0x80862811
> snd_soc_hda_codec:hda_hdev_attach: snd_hda_codec_generic hdaudioB0D2:
> no i915, skip registration for 0x80862811
> snd_hda_codec:snd_hda_codec_configure: hdaudio hdaudioB0D2: Unable to
> bind the codec
> snd_soc_avs 0000:00:1f.3: failed to config codec -19
> snd_soc_avs 0000:00:1f.3: Codec #2 probe error; disabling it...

Yeah the latter two are basically fallbacks, and I guess we can
disable them for ASoC case?  An additional patch like below.


thanks,

Takashi

--- a/sound/pci/hda/hda_bind.c
+++ b/sound/pci/hda/hda_bind.c
@@ -279,6 +279,10 @@ static int codec_bind_generic(struct hda_codec *codec)
 	if (codec->probe_id)
 		return -ENODEV;
 
+	/* no generic fallback for ASoC binding */
+	if (codec->bus->core.ext_ops)
+		return -ENODEV;
+
 	if (is_likely_hdmi_codec(codec)) {
 		codec->probe_id = HDA_CODEC_ID_GENERIC_HDMI;
 		request_codec_module(codec);