snd_hda fails to probe after 15 March

Hi Ariff and -current,

Some time after March 15, snd_hda started failing to attach to
pcm0 on my laptop.  I haven't managed to nail the change down to
a single commit yet, but I've attached the files:

    dmesg.boot-15       boot -v output of March 15 kernel
    dmesg.boot-25	boot -v output of March 25 kernel
    devinfo-15		devinfo -v output of March 15 kernel
    devinfo-25		devinfo -v output of March 25 kernel

There seems to be at least one more message in dmesg.boot-25 which seems
relevant to snd_hda failing to attach:

 pcm0: [MPSAFE]
 pcm0: [ITHREAD]
+pcm0: hdac_get_capabilities: Invalid rirb size (0)
+device_attach: pcm0 attach returned 6
 pcib1: <ACPI PCI-PCI bridge> irq 17 at device 28.0 on pci0

If you need anything more to troubleshoot this, let me know :)

- Giorgos