Re: [PATCH] ALSA: hda/hdmi: disable KAE for Intel Panther Lake

[Kai Vehmanen <kai.vehmanen@linux.intel.com>]

Hi Alexander,

On Fri, 12 Jun 2026, Alexander Kaplan wrote:

> That is probably just the sink.
> As long as KAE was never active in the display power cycle, my TV plays multichannel LPCM audibly on the front pair, even though its ELD advertises 2 channel LPCM only.
> The bug signal is the switch to multichannel itself.
> The first 6 or 8 channel stream after KAE activity plays silent, wedges the pin and everything after it stays silent.
[...]
> That said, after your LNL result I agree a PTL only model change is the wrong shape.
> I can gate the silent stream type per pin on the ELD connection type instead.
> DP pins fall back to the SILENT_STREAM_I915 path and native HDMI pins keep KAE, on all KAE platforms.
> That matches the failure boundary on both of our machines and keeps the power benefit where it works.
> If that shape works for you I will send it as v2.

gating on DP pin type is less than ideal as this would impact USB-C dock
usage, which is probably the most common scenario where the display audio 
keepalive helps (to ensure desktop/UI sounds are played out from the start 
and not eaten up by the HDMI/DP receiver taking their time waking up).

I'm asking around internally for more test results based on your findings, 
but one quick test to make if you have time:
--cut--
--- a/sound/hda/codecs/hdmi/intelhdmi.c
+++ b/sound/hda/codecs/hdmi/intelhdmi.c
@@ -445,6 +445,12 @@ static int i915_hsw_setup_stream(struct hda_codec *codec, hda_nid_t cvt_nid,
                                        stream_tag, format);

        if (spec->silent_stream_type == SILENT_STREAM_KAE && per_pin && per_pin->silent_stream) {
+               /* do not reenable KAE if multichannel streaming started */
+               if ((format & AC_FMT_TYPE_NON_PCM) || (format & AC_FMT_CHAN_MASK) > 1) {
+                       codec_dbg(codec, "HDMI: multichannel stream, disable KAE\n");
+                       return res;
+               }
+
--cut--

The driver has disabled KAE just before this, so this is worth a shot. 
If pin is still wedged, then the problem occurs already earlier in the 
sequence.

Br, Kai