Linux 5.10 fails to boot on my IceLake laptop, where 5.9 worked fine. I'm not sure whether it's a bug in ACPI or Soundwire subsystem, so I'm sending this to both lists. The W taint flag is because of an unrelated nouveau failure (It was busted on 5.9, and is still on 5.10). Full kernel log down below. It's from a distro kernel, but I can build my own kernel with patches if needed.
Please try to add a check for handle against NULL to snd_intel_dsp_check_soundwire() after
handle = ACPI_HANDLE(&pci->dev);
and see if this makes any difference.
This should check handle against NULL anyway, even if it didn't crash later on.
Is there a way you can share the DSDT?
The only thing we do in that sdw_intel_acpi_scan() function is check for an _ADR and read two _DSD properties. I think it's been 2 years since we wrote it and never had an issue, never say never I guess...
If you want to bypass this problem for the time being, you can add a kernel option in /etc/modprobe.d/alsa-base.conf
options snd-intel-dspcfg dsp_driver=1
that will force the use of the HDaudio legacy driver and bypass the driver autodetection.