Most recent kernel where this bug did not occur:
Distribution: Gentoo
Hardware Environment: Toshiba P100 series Laptops
Software Environment:
Problem Description:  the Conexant patch for the HD audio driver only enables
audio when "acpi=off irqpoll" is added to the kernel command line.

Steps to reproduce:

With acpi mode at default, audio is faint, suggesting EAPD bit is not being
enabled.  With acpi=off, audio works, but the following kernel messages were
seen in dmesg:

 Nov  5 21:42:25 creeper irq 16: nobody cared (try booting with the
"irqpoll" option)
 Nov  5 21:42:25 creeper [<c0130ce3>] __report_bad_irq+0x2b/0x69
 Nov  5 21:42:25 creeper [<c0130ecd>] note_interrupt+0x1ac/0x1e3
 Nov  5 21:42:25 creeper [<c027e827>] usb_hcd_irq+0x23/0x50
 Nov  5 21:42:25 creeper [<c01304eb>] handle_IRQ_event+0x23/0x49
 Nov  5 21:42:25 creeper [<c01305c3>] __do_IRQ+0xb2/0xe6
 Nov  5 21:42:25 creeper [<c0104b6d>] do_IRQ+0x43/0x52
 Nov  5 21:42:25 creeper [<c01031f6>] common_interrupt+0x1a/0x20
 Nov  5 21:42:25 creeper [<c0101716>] mwait_idle+0x25/0x38
 Nov  5 21:42:25 creeper [<c01016db>] cpu_idle+0x5e/0x74
 Nov  5 21:42:25 creeper handlers:
 Nov  5 21:42:25 creeper [<c027e804>] (usb_hcd_irq+0x0/0x50)
 Nov  5 21:42:25 creeper Disabling IRQ #16

Adding "noirq" allows audio to work without error messages, but other acpi
functions are not available (suspend, etc).