What are fixed events and GPE(s)?
After the system is up and running, ACPI works with the OS to handle any ACPI events that occur via an interrupt. This interrupt invokes ACPI events in one of two general ways: fixed events and general purpose events (GPEs).

Fixed events are ACPI events that have a predefined meaning in the ACPI specification. These fixed events include actions like pressing the power button or ACPI timer overflows. These events are handled directly by the OS handlers.

GPEs are ACPI events that are not predefined by the ACPI specification. These events are usually handled by evaluating control methods, which are objects in the namespace and can access system hardware. When the ACPI subsystem evaluates the control method with the AML interpreter, the GPE object handles the events according to the OS’s implementation. Typically this might involve issuing a notification to a device to invoke the device driver to perform a function.
Below is an instruction that describes a task. Write a response that appropriately completes the request. ### Instruction: What are fixed events and GPE(s)? ### Response: After the system is up and running, ACPI works with the OS to handle any ACPI events that occur via an interrupt. This interrupt invokes ACPI events in one of two general ways: fixed events and general purpose events (GPEs).

Fixed events are ACPI events that have a predefined meaning in the ACPI specification. These fixed events include actions like pressing the power button or ACPI timer overflows. These events are handled directly by the OS handlers.

GPEs are ACPI events that are not predefined by the ACPI specification. These events are usually handled by evaluating control methods, which are objects in the namespace and can access system hardware. When the ACPI subsystem evaluates the control method with the AML interpreter, the GPE object handles the events according to the OS’s implementation. Typically this might involve issuing a notification to a device to invoke the device driver to perform a function. 