From: "Jürgen Lambrecht" <J.Lambrecht@televic.com>
To: eCos Discussion <ecos-discuss@ecos.sourceware.org>
Subject: Re: [ECOS] Possible fix for interrupt latency problems on Arm
Date: Mon, 31 Jul 2006 08:32:00 -0000 [thread overview]
Message-ID: <44CDBFC1.1050909@televic.com> (raw)
In-Reply-To: <44B7850A.4050508@ovus.co.uk>
Hello Mike,
I'm just back from holidays - you didn't receive any reply on your mail?
I also use an ARM (ARM7TDMI, eb55 board based), so I'm interested in the
problem. I don't have interrupt latency problems (yet), but I will ask my
colleague.
This is list is normally a good place to start committing modifications..
For the patch, you must send a diff (you can find examples in the mailing
list), and :
"Next time, please send to ecos-patches@ecos.sourceware.org. Also
include a ChangeLog entry so we don't have to fabricate one."
Kind regards,
Juergen
---
Jürgen Lambrecht
Development Engineer
Televic Transport Systems
http://www.televic.com
Televic NV / SA (main office)
Leo Bekaertlaan 1
B-8870 Izegem
Tel: +32 (0)51 303045
Fax: +32 (0)51 310670
Mike wrote:
> I have been looking at why my Arm LPC2220 board occasionally gets
> terrible interrupt latencies. This happens particularly when the
> interrupt I'm interested in occurs whilst ecos is doing processing after
> a TIMER0 (ecos RTC) interrupt.
>
> It seems that interrupt_end() is called from
> hal/arm/arch/current/src/vectors.s with interrupts disabled, whereas it
> looks to me like interrupt_end() has been designed to run with
> interrupts enabled in order for DSRs to be interruptible.
>
> I have modified my own vectors.s by inserting the following immediately
> before the call to interrupt_end():
> // Enable interrupts
> mrs r4,cpsr
> bic r4,r4,#CPSR_IRQ_DISABLE|CPSR_FIQ_DISABLE
> msr cpsr,r4
>
> This seems to work for me, but I would appreciate feedback if this is a
> sane and wise thing to do.
>
> As a newbie, how do I submit such modifications for inclusion in the
> repository?
>
> Thanks,
> Mike
>
>
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next prev parent reply other threads:[~2006-07-31 8:32 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-14 11:50 Mike
2006-07-31 8:32 ` Jürgen Lambrecht [this message]
2006-07-31 10:21 ` Nick Garnett
2006-08-03 15:37 ` Mike
2006-08-08 8:59 ` [ECOS] embedded SMTP client Laurie Gellatly
2006-10-16 11:33 ` [ECOS] Interrupts and new ethernet driver Laurie Gellatly
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