When no SoundWire machine driver matches the ACPI-reported configuration, hda_sdw_machine_select() builds a default machine from the enumerated SoundWire peripherals. The link mask and the per-peripheral adr_d entries are generated by iterating over every entry in hdev->sdw->peripherals, including peripherals that never attached to the bus.

Some platforms declare SoundWire peripherals in ACPI that are not physically populated. On the ASUS Zenbook S14 UX5406AA (PCI SSID 1043:1464) the BIOS declares an RT722 (025d:0722) on link 3 that stays SDW_SLAVE_UNATTACHED, alongside the physically present CS42L43. The phantom peripheral adds a second SimpleJack function on the same link, whose DAI name collides with the CS42L43 one:

kobject_add_internal failed for SDW3-Playback-SimpleJack with -EEXIST
sof_sdw sof_sdw: probe with driver sof_sdw failed with error -12

so card registration fails and only HDMI/Loopback remain.

Skip peripherals whose status is SDW_SLAVE_UNATTACHED when computing the link mask and when generating the adr_d entries, so the default machine reflects only hardware that is actually present, and bail out if no peripheral is attached.

Testing

Tested on ASUS Zenbook S14 UX5406AA (Panther Lake, PCI SSID 1043:1464,
CS42L43 + 4x CS35L56 over SoundWire). Without this patch, card
registration fails with -EEXIST / -12 because a phantom RT722
(025d:0722) declared in ACPI on link 3 never attaches and collides the
SDW3-Playback-SimpleJack DAI with the CS42L43. With the patch the
sof-soundwire card registers, the Speaker PCM appears, and all four
CS35L56 amplifiers attach and load their 10431464 firmware/calibration.

Note: a separate channel-routing limitation (the default machine selects
sof-sdca-2amp for a 4-amp board, leaving one side silent) is independent
of this fix and will be addressed separately.