Skip site navigation (1)Skip section navigation (2)
Date:      Mon, 18 Feb 2008 00:19:30 +0800
From:      Erich Dollansky <oceanare@pacific.net.sg>
To:        Andriy Gapon <avg@icyb.net.ua>
Cc:        freebsd-hackers@freebsd.org
Subject:   Re: multiple interrupts between cli and sti
Message-ID:  <47B85E92.9010206@pacific.net.sg>
In-Reply-To: <47B855C0.4010703@icyb.net.ua>
References:  <47B855C0.4010703@icyb.net.ua>

next in thread | previous in thread | raw e-mail | index | archive | help
Hi,

Andriy Gapon wrote:

I cannot tell you if this is still the same for modern designs.

> ... -> iret -> interrupted again

This was the behaviour earlier.
> 
> Is this a deterministic behavior ? Or some timings are at play?

The PIC should never release the Interrupt signal to the CPU as long as 
a single interrupt is not serviced.

But the 8259 can be programmed to trigger via level or slope.

So, this behaviour is only seen when level triggering is used.

As I said at the bginning, I do not know how current designs handle it.

Erich



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?47B85E92.9010206>