* irq_disable() not working
@ 2008-09-23 9:08 Wolfgang Grandegger
2008-09-23 9:20 ` Benjamin Herrenschmidt
0 siblings, 1 reply; 2+ messages in thread
From: Wolfgang Grandegger @ 2008-09-23 9:08 UTC (permalink / raw)
To: linuxppc-dev
Hello,
I'm trying to understand how irq_disable() is supposed to work on
PowerPC systems. Most PowerPC PIC do *not* implement the enable and
disable, but just the unmask and mask methods, e.g:
http://lxr.linux.no/linux+v2.6.26.5/arch/powerpc/sysdev/mpic.c#L867
The irq_disable() function will then call the default function
default_disable():
http://lxr.linux.no/linux+v2.6.26.5/kernel/irq/chip.c#L234
which does not *nothing*. I do not see how the interrupt gets disabled
on the hardware level. Obviously I have missed something. TIA for
clarification.
Wolfgang.
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: irq_disable() not working
2008-09-23 9:08 irq_disable() not working Wolfgang Grandegger
@ 2008-09-23 9:20 ` Benjamin Herrenschmidt
0 siblings, 0 replies; 2+ messages in thread
From: Benjamin Herrenschmidt @ 2008-09-23 9:20 UTC (permalink / raw)
To: Wolfgang Grandegger; +Cc: linuxppc-dev
On Tue, 2008-09-23 at 11:08 +0200, Wolfgang Grandegger wrote:
> I'm trying to understand how irq_disable() is supposed to work on
> PowerPC systems. Most PowerPC PIC do *not* implement the enable and
> disable, but just the unmask and mask methods, e.g:
>
> http://lxr.linux.no/linux+v2.6.26.5/arch/powerpc/sysdev/mpic.c#L867
>
> The irq_disable() function will then call the default function
> default_disable():
>
> http://lxr.linux.no/linux+v2.6.26.5/kernel/irq/chip.c#L234
>
> which does not *nothing*. I do not see how the interrupt gets disabled
> on the hardware level. Obviously I have missed something. TIA for
> clarification.
Lazy masking ? ie, look what happens if the irq happens while disabled.
Ben.
^ permalink raw reply [flat|nested] 2+ messages in thread
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