From: Alexander Graf <agraf@suse.de>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Rob Herring <rob.herring@linaro.org>,
"Michael S. Tsirkin" <mst@redhat.com>,
QEMU Developers <qemu-devel@nongnu.org>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Claudio Fontana <claudio.fontana@huawei.com>,
"stuart.yoder@freescale.com" <stuart.yoder@freescale.com>,
alvise rigo <a.rigo@virtualopensystems.com>
Subject: Re: [Qemu-devel] [PATCH 2/4] pci: Add generic PCIe host bridge
Date: Mon, 12 Jan 2015 22:06:38 +0100 [thread overview]
Message-ID: <54B4375E.3070200@suse.de> (raw)
In-Reply-To: <CAFEAcA-RGoJtrBKCQK+NmVfXo+bu2JFBCZG-XdroW08DHsY_7Q@mail.gmail.com>
On 12.01.15 21:08, Peter Maydell wrote:
> On 12 January 2015 at 17:38, Alexander Graf <agraf@suse.de> wrote:
>> I'd prefer to keep things as easy as we humanly can for now. Then add
>> MSI. And if we then realize that we still need 4 rather than 1 shared
>> interrupt lines we can still change it :)
>
> Except that that would be a breaking change, so I would prefer
> to think ahead where possible; at some point there will come
> a time when we really can't make breaking changes to this
> board any more...
Works for me, then we stay at a single interrupt line. The only reason
we have 4 in PCI is that back in the day you could have non-sharing PCI
devices that were essentially ISA ones.
If you actually care about interrupt latency and performance you will
want more than 4 IRQ lines, so you'll want MSI.
Alex
next prev parent reply other threads:[~2015-01-12 21:06 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-06 16:03 [Qemu-devel] [PATCH 0/4] ARM: Add support for a generic PCI Express host bridge Alexander Graf
2015-01-06 16:03 ` [Qemu-devel] [PATCH 1/4] pci: Split pcie_host_mmcfg_map() Alexander Graf
2015-01-12 16:28 ` Claudio Fontana
2015-01-06 16:03 ` [Qemu-devel] [PATCH 2/4] pci: Add generic PCIe host bridge Alexander Graf
2015-01-12 16:29 ` Claudio Fontana
2015-01-12 17:36 ` alvise rigo
2015-01-12 17:38 ` Alexander Graf
2015-01-12 20:08 ` Peter Maydell
2015-01-12 21:06 ` Alexander Graf [this message]
2015-01-12 21:20 ` Peter Maydell
2015-01-13 0:13 ` Alexander Graf
2015-01-13 10:07 ` Peter Maydell
2015-01-13 9:09 ` Claudio Fontana
2015-01-06 16:03 ` [Qemu-devel] [PATCH 3/4] arm: Add PCIe host bridge in virt machine Alexander Graf
2015-01-07 15:52 ` Claudio Fontana
2015-01-07 21:47 ` Alexander Graf
2015-01-08 12:55 ` Claudio Fontana
2015-01-08 13:26 ` Alexander Graf
2015-01-08 15:01 ` Claudio Fontana
2015-01-12 16:23 ` Claudio Fontana
2015-01-12 16:35 ` Alexander Graf
2015-01-08 13:36 ` alvise rigo
2015-01-08 10:31 ` Peter Maydell
2015-01-08 12:30 ` Claudio Fontana
2015-01-12 16:20 ` Claudio Fontana
2015-01-12 16:36 ` Alexander Graf
2015-01-12 16:49 ` alvise rigo
2015-01-12 16:57 ` Alexander Graf
2015-01-06 16:03 ` [Qemu-devel] [PATCH 4/4] arm: enable Bochs PCI VGA Alexander Graf
2015-01-06 16:16 ` Peter Maydell
2015-01-06 21:08 ` Alexander Graf
2015-01-06 21:28 ` Peter Maydell
2015-01-06 21:42 ` Alexander Graf
2015-01-07 6:22 ` Paolo Bonzini
2015-01-07 13:52 ` [Qemu-devel] [PATCH 0/4] ARM: Add support for a generic PCI Express host bridge Claudio Fontana
2015-01-07 14:07 ` Alexander Graf
2015-01-07 14:26 ` Claudio Fontana
2015-01-07 14:36 ` Alexander Graf
2015-01-07 15:16 ` Claudio Fontana
2015-01-07 16:31 ` Peter Maydell
2015-01-12 16:24 ` Claudio Fontana
2015-01-21 12:59 ` Claudio Fontana
2015-01-21 13:01 ` Alexander Graf
2015-01-21 13:02 ` Peter Maydell
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