Message-Signaled Interrupts

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Message-Signaled Interrupts ( MSI ) are a type of interrupt available in computer systems with PCI 2.2 and higher. The MSI-compatible devices do not request treatment via an electronic signal, but via messages that are written to a specific address via the PCI bus.

Important advantages of this type of interrupt are:

  • Devices can generate different interrupts (messages)
  • Interrupt sharing is avoided (no "fixed" number as with interrupt signal lines)
  • No confirmation, therefore faster