Re: [PATCH 2.6.16] Shared interrupts sometimes lost

[Lee Revell <rlrevell@joe-job.com>]

On Sat, 2006-04-08 at 14:10 +1000, Neil Brown wrote:
> 
>  To explain what I think is happening, let me start with a very simple
>  case.  A number of PCI devices (this one included) have a number of
>  events which can trigger an interrupt.  The events which are current
>  are presented as bits in a register, and are ORed together (and
>  possibly masked by another register) to make the IRQ line.
>  When 1's are written to any bits in this register, it acknowledges
>  the event and clears the bit.
>  A typical code fragment is 
>    events = read_register(INTERRUPTS);
>    write_register(INTERRUPTS, events);
>    ... handle each 1 bits in events ....
> 

Isn't a more typical IRQ handler:

while (events = read_register(INTERRUPTS) != 0) {
	...handle each bit in events and ACK it...
}

Lee

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