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

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

Hello Alexander,

On Sat, 20 Jun 2026, Alexander Kaplan wrote:

> thanks for the quick test patch.
> 
> I ran it on Panther Lake with PTL kept at MODEL_ADLP so the KAE path is
> active.
[...]
>   # speaker-test -D hw:0,3 -c6   (silent)
>   hdmi_pin_setup_infoframe: pin NID=0xa channels=6 ca=0x0b
>   HDMI: KAE 0 cvt-NID=0x3
>   hdmi_pin_hbr_setup: NID=0xa, pinctl=0x40
>   i915_hsw_setup_stream: HDMI: multichannel stream, disable KAE
> 
>   # speaker-test -D hw:0,3 -c2   (stays silent)
>   hdmi_pin_setup_infoframe: pin NID=0xa channels=2 ca=0x00
>   HDMI: KAE 0 cvt-NID=0x3
>   hdmi_pin_hbr_setup: NID=0xa, pinctl=0x40
>   HDMI: KAE 1 cvt-NID=0x3
[...]
> So the wedge happens earlier in the sequence, as you suspected, not at
> the re-arm.
> The trigger looks like the multichannel DMA start itself once the KAE
> block has been active in the running power cycle, below the codec verb
> level.

thanks for the quick test. I'm working with our display folks to test
this out with some Synaptic DP-alt HDMI converter. This same test
worked ok with one converter (Lenovo USB-C to HDMI Adapter GX90K37871),
but I'll try to get someone to test with more converters. Given you see
this with multiple DP-HDMI converters, we should be able to hit this.

And a bit suspicious how this could work with the Lenovo adapter. I wonder 
if we have something else differing in the test setup. Given you cannot 
recover by unplugging and reconnecting the converter, it would seem the 
issue is on transmitter side and should be visible with all DP-alt 
receivers.

I filed a bug to Xe/display to track this effort:
https://gitlab.freedesktop.org/drm/xe/kernel/-/work_items/8412

Br, Kai