From: Markus Armbruster <armbru@redhat.com>
To: Blue Swirl <blauwirbel@gmail.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 8/9] isa: refine irq reservations
Date: Mon, 14 Sep 2009 22:09:35 +0200 [thread overview]
Message-ID: <87ab0xuw3k.fsf@pike.pond.sub.org> (raw)
In-Reply-To: <f43fc5580909140955t4f914f26n5c7f7a247b9b6e64@mail.gmail.com> (Blue Swirl's message of "Mon\, 14 Sep 2009 19\:55\:23 +0300")
Blue Swirl <blauwirbel@gmail.com> writes:
> On Mon, Sep 14, 2009 at 6:49 PM, Gerd Hoffmann <kraxel@redhat.com> wrote:
>> There are a few cases where IRQ sharing on the ISA bus is used and
>> possible. In general only devices of the same kind can do that.
>> A few use cases:
>>
>> * serial lines 1+3 share irq 4
>> * serial lines 2+4 share irq 3
>> * parallel ports share irq 7
>> * ppc/prep: ide ports share irq 13
>
> There is another ppc/prep case where RTC and m48t59 share irq 8. The
> attached patch converts m48t59 to ISA and makes this more visible.
>
> Does sharing of IRQs really have to be fatal? Wasn't ISA bus edge
> triggered and so IRQ sharing was a bit unreliable (but not completely
> broken) also on real HW?
If I remember correctly (and that's a considerable if), sufficiently
well-behaved hardware with sufficiently smart drivers could share IRQs.
next prev parent reply other threads:[~2009-09-14 20:09 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-14 15:49 [Qemu-devel] [PATCH 0/9] ide: convert to qdev Gerd Hoffmann
2009-09-14 15:49 ` [Qemu-devel] [PATCH 1/9] qdev/pci: add pci_create_noinit() Gerd Hoffmann
2009-09-14 15:49 ` [Qemu-devel] [PATCH 2/9] support media=cdrom for if=none Gerd Hoffmann
2009-09-14 15:49 ` [Qemu-devel] [PATCH 3/9] split away drive init from ide_init2() Gerd Hoffmann
2009-09-14 15:49 ` [Qemu-devel] [PATCH 4/9] ide/qdev: add ide bus Gerd Hoffmann
2009-09-14 15:49 ` [Qemu-devel] [PATCH 5/9] ide/pci: fix indention Gerd Hoffmann
2009-09-14 15:49 ` [Qemu-devel] [PATCH 6/9] ide/pci: convert to qdev Gerd Hoffmann
2009-09-14 15:49 ` [Qemu-devel] [PATCH 7/9] ide/isa: " Gerd Hoffmann
2009-09-14 17:23 ` Blue Swirl
2009-09-14 17:46 ` Blue Swirl
2009-09-15 9:33 ` Gerd Hoffmann
2009-09-15 20:10 ` Blue Swirl
2009-09-14 15:49 ` [Qemu-devel] [PATCH 8/9] isa: refine irq reservations Gerd Hoffmann
2009-09-14 16:55 ` Blue Swirl
2009-09-14 20:09 ` Markus Armbruster [this message]
2009-09-15 7:23 ` Gerd Hoffmann
2009-09-15 19:08 ` Blue Swirl
2009-09-14 15:49 ` [Qemu-devel] [PATCH 9/9] unbreak ppc/prep Gerd Hoffmann
2009-09-23 19:00 ` [Qemu-devel] [PATCH 0/9] ide: convert to qdev Markus Armbruster
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