About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Documentation / IRQ.txt




Custom Search

Based on kernel version 4.13.3. Page generated on 2017-09-23 13:55 EST.

1	===============
2	What is an IRQ?
3	===============
4	
5	An IRQ is an interrupt request from a device.
6	Currently they can come in over a pin, or over a packet.
7	Several devices may be connected to the same pin thus
8	sharing an IRQ.
9	
10	An IRQ number is a kernel identifier used to talk about a hardware
11	interrupt source.  Typically this is an index into the global irq_desc
12	array, but except for what linux/interrupt.h implements the details
13	are architecture specific.
14	
15	An IRQ number is an enumeration of the possible interrupt sources on a
16	machine.  Typically what is enumerated is the number of input pins on
17	all of the interrupt controller in the system.  In the case of ISA
18	what is enumerated are the 16 input pins on the two i8259 interrupt
19	controllers.
20	
21	Architectures can assign additional meaning to the IRQ numbers, and
22	are encouraged to in the case  where there is any manual configuration
23	of the hardware involved.  The ISA IRQs are a classic example of
24	assigning this kind of additional meaning.
Hide Line Numbers
About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Information is copyright its respective author. All material is available from the Linux Kernel Source distributed under a GPL License. This page is provided as a free service by mjmwired.net.