Re: ARM Linux Suitability for Real-time Application

From: Russell King
Date: Wed Jun 22 2005 - 12:45:12 EST

On Wed, Jun 22, 2005 at 09:52:40AM -0700, Daniel Walker wrote:
> On Wed, 22 Jun 2005, Russell King wrote:
> > If you're just after some background process to run off interrupts with
> > minimal interrupt latency, the good news is that you don't have to modify
> > the kernel on ARM, and you certainly don't need any RT patches.
> >
> > If you use the FIQ, then your FIQ latency will be the time it takes the
> > CPU to enter your FIQ function. Since the kernel _never_ disables FIQs
> > in any way, FIQs have ultimate priority over everything else in the
> > system.
> >
> Aren't FIQ's only on some ARM's ?

Yes, but please read the original mail. I think you'll find my reply
is completely relevant to the question being posed, which was based
upon the AT91RM9200 SoC.

Russell King
Linux kernel 2.6 ARM Linux -
maintainer of: 2.6 Serial core
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