Hi all xhci_msi_irq is the interrupt handler for xhci, the controller it self is a PCI device, on my system it is a Intel chip. I have multiple USB device connect to this USB host controller, xhci_msi_irq is interrupt handler for the PCI device(USB Host controller). Is it possible to have multiple IRQ, and different IRQ for different USB device? If so how? the chip(USB Host controller) should know which USB device’s transaction, When the chip decide to assert an interrupt, it should be a reason for a specified USB device, then assert a correspondence MSI interrupt. Thanks. sudo lspci -s 00:14.0 -v 00:14.0 USB controller: Intel Corporation Device a2af (prog-if 30 [XHCI]) Subsystem: Dell Device 0738 Flags: bus master, medium devsel, latency 0, IRQ 29 Memory at 38003ff10000 (64-bit, non-prefetchable) [size=64K] Capabilities: [70] Power Management version 2 Capabilities: [80] MSI: Enable+ Count=1/8 Maskable- 64bit+ Kernel driver in use: xhci_hcd Regards