Ah, the logs are fun too... Unplugging headphone: Jul 30 14:13:00 aieee kernel: [14938.291225] ALSA /usr/src/modules/alsa-driver/pci/hda/../../alsa-kernel/pci/hda/hda_intel.c:610: hda_intel: No response from codec, disabling MSI: last cmd=0x015f0900 Jul 30 14:13:00 aieee kernel: [14939.292014] ALSA /usr/src/modules/alsa-driver/pci/hda/../../alsa-kernel/pci/hda/hda_intel.c:623: hda_intel: azx_get_response timeout, switching to polling mode: last cmd=0x015f0900 Huh. OK... Re-loading driver: Jul 30 14:14:02 aieee kernel: [15000.903539] ACPI: PCI interrupt for device 0000:00:1b.0 disabled Jul 30 14:14:05 aieee kernel: [15003.734856] ACPI: PCI Interrupt 0000:00:1b.0[A] -> GSI 16 (level, low) -> IRQ 16 So ACPI thinks it's on 16, but the driver thinks it's on 219: 219: 3063731 PCI-MSI-edge HDA Intel If I run JACK, everything appears to work, and the interrupts counter on INT-219 is incrementing plenty fast. -ken