From: Avi Kivity <avi@redhat.com>
To: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Jan Kiszka <jan.kiszka@web.de>,
Matthew Ogilvie <mmogilvi_qemu@miniinfo.net>,
qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH v5 5/6] i8259: fix so that dropping IRQ level always clears the interrupt request
Date: Tue, 11 Sep 2012 15:57:51 +0300 [thread overview]
Message-ID: <504F354F.7070202@redhat.com> (raw)
In-Reply-To: <alpine.LFD.2.00.1209101341160.8926@eddie.linux-mips.org>
On 09/10/2012 04:09 PM, Maciej W. Rozycki wrote:
>
>> > No, this is about the PIC, not the CPU interrupt inputs.
>>
>> I see, the interrupt is still sent to the processor; but IRR reflects
>> that status of the input line, not a "pending interrupt" status.
>
> Not really, this is still a "pending interrupt" status.
>
> For level-triggered inputs the state of IRR bits do indeed follow the
> respective IRx inputs (taking the IMR into account). For edge-triggered
> inputs the relevant IRR bit is set by a leading edge on its corresponding
> IRx input and cleared when the interrupt is acknowledged (either with an
> INTA bus cycle or by a data read bus cycle issued to the PIC armed with an
> OCW3 that has had the POLL command bit set) OR with a trailing edge on IRx
> (again, all this takes the IMR into account). At this point another
> leading edge is required for the IRR bit to be set again, that is merely
> keeping the IRx input's level active won't trigger another interrupt.
Ok, thanks, that explains it for me.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2012-09-11 12:58 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-10 1:27 [Qemu-devel] [PATCH v5 0/6] Running Microport UNIX (ca 1987) Matthew Ogilvie
2012-09-10 1:27 ` [Qemu-devel] [PATCH v5 1/6] fix some debug printf format strings Matthew Ogilvie
2012-09-10 1:27 ` [Qemu-devel] [PATCH v5 2/6] vl: fix -hdachs/-hda argument order parsing issues Matthew Ogilvie
2012-09-10 1:27 ` [Qemu-devel] [PATCH v5 3/6] qemu-options.hx: mention retrace= VGA option Matthew Ogilvie
2012-09-10 1:27 ` [Qemu-devel] [PATCH v5 4/6] vga: add some optional CGA compatibility hacks Matthew Ogilvie
2012-09-10 1:27 ` [Qemu-devel] [PATCH v5 5/6] i8259: fix so that dropping IRQ level always clears the interrupt request Matthew Ogilvie
2012-09-10 8:56 ` Avi Kivity
2012-09-10 9:09 ` Jan Kiszka
2012-09-10 9:18 ` Avi Kivity
2012-09-10 9:33 ` Jan Kiszka
2012-09-10 13:09 ` Maciej W. Rozycki
2012-09-11 12:57 ` Avi Kivity [this message]
2012-09-11 4:32 ` Matthew Ogilvie
2012-09-11 9:05 ` Jan Kiszka
2012-09-11 12:58 ` Avi Kivity
2012-11-19 15:28 ` BALATON Zoltan
2012-11-20 5:05 ` Matthew Ogilvie
2012-09-10 1:27 ` [Qemu-devel] [PATCH v5 6/6] i8259: refactor pic_set_irq level logic Matthew Ogilvie
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