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Replace SA_xxx IRQ flags with the IRQF_xxx ones

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The SA_xxx flags has been removed for years. Nowadays the kernel uses
the IRQF_xxx flags to specify IRQ behaviors. Adjust the descriptions
in the book accordingly.
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Yo-Jung Lin 2024-04-09 19:39:18 +08:00
parent 470fbcd97d
commit b9a10fe17b
1 changed files with 8 additions and 1 deletions
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lkmpg.tex
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@ -1879,7 +1879,14 @@ People still interested in more details, might want to refer to "APIC" now.
This function receives the IRQ number, the name of the function, flags, a name for \verb|/proc/interrupts| and a parameter to be passed to the interrupt handler.
Usually there is a certain number of IRQs available.
How many IRQs there are is hardware-dependent.
The flags can include \cpp|SA_SHIRQ| to indicate you are willing to share the IRQ with other interrupt handlers (usually because a number of hardware devices sit on the same IRQ) and \cpp|SA_INTERRUPT| to indicate this is a fast interrupt.
The flags can be used for specify behaviors of the IRQ.
For example, use \cpp|IRQF_SHARED| to indicate you are willing to share the IRQ with other interrupt handlers (usually because a number of hardware devices sit on the same IRQ); use the \cpp|IRQF_ONESHOT| to indicate that the IRQ is not reenabled after the handler finished.
It should be noted that in some materials, you may encouter another set of IRQ flags named with the \cpp|SA| prefix.
For example, the \cpp|SA_SHIRQ| and the \cpp|SA_INTERRUPT|.
Those are the the IRQ flags in the older kernels.
They have been removed completely.
Today only the \cpp|IRQF| flags are in use.
This function will only succeed if there is not already a handler on this IRQ, or if you are both willing to share.
\subsection{Detecting button presses}