From: Randy <randyqiuxy@hotmail.com>
To: "Stanislav Meduna" <stano@meduna.org>
Cc: "eCos Discussion" <ecos-discuss@sourceware.org>
Subject: Re: Re: [ECOS] why should ISR arrange that the same interrupt would not recur until DSR completed?
Date: Sun, 31 Mar 2013 14:48:00 -0000 [thread overview]
Message-ID: <BLU0-SMTP36883F43DD5BCCFFF94355FC3DD0@phx.gbl> (raw)
In-Reply-To: <5158269C.5000804@meduna.org>
Hi Stano,
Thanks for your rapid response.
>On 31.03.2013 10:10, Randy wrote:
>
>> But why? If other interrupt could be enable when processing DSR, why
>> is the same interrupt not allowed?
>
>1) Other interrupt does not need to synchronize access to the hardware
>and/or data structures shared between the ISR and corresponding DSR.
That's right, it should be the reason why we don't allow the interrupt to recur during DSR.
>Remember, neither the ISR nor DSR can block.
I know this rule, but I'd like to ask you why.
I think that one DSR interrupted by other interrupt could continue to finish the remainder parts when it reschedule to current thread, then,
why wait-semaphore in DSR which cause to switch to another thread is prevented by scheduler? This maybe because scheduler is locked and it could not work, but why don't we enable this function in DSR?
>Disabling interrupts outside of interrupt handlers is generally frowned upon.
I don't see this, could you please make it more clearly?
>2) The list of pending DSRs is now upper bounded. With the same
>interrupt enabled it would become unbounded.
I'd like to know which case could cause a pending DSR?
Does one DSR interrupted by other interrupt could become a pending DSR? No, right?
>Regards
>--
> Stano
>
>
>--
>Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
>and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss
>
>
Thanks a lot..
Best regards,
Randy
next prev parent reply other threads:[~2013-03-31 14:48 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-28 14:40 [ECOS] Is eCosPro a fork of eCos? Liam Knight
2013-03-28 16:25 ` [ECOS] " John Dallaway
2013-03-28 18:40 ` Liam Knight
2013-03-31 8:08 ` [ECOS] why should ISR arrange that the same interrupt would not recur until DSR completed? Randy
2013-03-31 12:06 ` Stanislav Meduna
2013-03-31 14:48 ` Randy [this message]
2013-04-01 11:59 ` Stanislav Meduna
2013-04-07 12:05 ` Randy
2013-04-07 13:21 ` Stanislav Meduna
2013-04-10 8:36 ` [ECOS] put unmask in ISR rather than DSR causing interrupt lost Randy
2013-04-10 9:27 ` 回复: " Randy
2013-04-14 11:39 ` 回复: " Randy
2013-04-18 2:50 ` [ECOS] why did not enable interrupt before call pending dsr while not use interrupt stack Randy
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