Registering shared & unshared interrupt handlers

[Jay Aurabind]

Oops, I though IRQ_DISABLED was the opposite of IRQF_SHARED. Sorry.
Consider the question not asked :P


On 17 February 2014 12:06, Jay Aurabind <jay.aurabind at gmail.com> wrote:

>  Dear all,
>
> I've been going through Robert Love's LKD. Here is an excerpt from it
> regarding registration of interrupt handlers:
>
> "When request_irq() is called with IRQF_SHARED specified, the call
> succeeds only if the interrupt line is currently not registered, or if all
> registered handlers on the line also specified IRQF_SHARED. Shared
> handlers, however, can mix usage of IRQF_DISABLED."
>
> As far as I understand, the first sentence tells that a line currently
> having shared handlers *will only have* handlers registered with
> IRQF_SHARED flag in the past. Correct ?
>
> If a interrupt line has been registered by a handler specified as non
> shared, then whats the point in allowing a new handler with a "shared" flag
> registering to the same line ? So how does the mixing of shared and
> unshared interrupt handlers for the same line go together as mentioned by
> the 2nd sentence ?
>
> Or does it mean that a shared handler which already succeeded the
> registration can further register a non shared and shared interrupt
> handlers? ( That doesnt make sense, but still... )  ? Simply put, can
> someone please elaborate on the second sentence I quoted from the book ?
>
>
> Thanks and Regards,
> Aurabindo J
>



-- 

Thanks and Regards,
*Aurabindo J*
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