Documentation/core-api/irq/concepts.rst
Source file repositories/reference/linux-study-clean/Documentation/core-api/irq/concepts.rst
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- System
- Linux kernel
- Corpus path
Documentation/core-api/irq/concepts.rst- Extension
.rst- Size
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- 26
- Domain
- Support Tooling And Documentation
- Bucket
- Documentation
- Inferred role
- Support Tooling And Documentation: documentation
- Status
- atlas-only
Why This File Exists
Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
- Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
Dependency Surface
- No C-style include directives detected by the generator.
Detected Declarations
- No top-level syscall, struct, function, initcall, or export declaration detected by the generator.
Annotated Snippet
===============
What is an IRQ?
===============
An IRQ is an interrupt request from a device. Currently, they can come
in over a pin, or over a packet. Several devices may be connected to
the same pin thus sharing an IRQ. Such as on legacy PCI bus: All devices
typically share 4 lanes/pins. Note that each device can request an
interrupt on each of the lanes.
An IRQ number is a kernel identifier used to talk about a hardware
interrupt source. Typically, this is an index into the global irq_desc
array or sparse_irqs tree. But except for what linux/interrupt.h
implements, the details are architecture specific.
An IRQ number is an enumeration of the possible interrupt sources on a
machine. Typically, what is enumerated is the number of input pins on
all of the interrupt controllers in the system. In the case of ISA,
what is enumerated are the 8 input pins on each of the two i8259
interrupt controllers.
Architectures can assign additional meaning to the IRQ numbers, and
are encouraged to in the case where there is any manual configuration
of the hardware involved. The ISA IRQs are a classic example of
assigning this kind of additional meaning.Annotation
- Atlas domain: Support Tooling And Documentation / Documentation.
- Implementation status: atlas-only.
Implementation Notes
- This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
- Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
- Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.