lkml.org 
[lkml]   [2006]   [Apr]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 2.6.16] Shared interrupts sometimes lost
From
Date
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

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-04-08 18:34    [W:0.076 / U:0.092 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site