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@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*