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Date: Sun, 10 Jun 2012 20:04:26 +0300
From: "Michael S. Tsirkin" <mst@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 05/13] pci: Add pci_device_route_intx_to_irq
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To: Jan Kiszka <jan.kiszka@web.de>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>, Alex Williamson <alex.williamson@redhat.com>, qemu-devel <qemu-devel@nongnu.org>

On Sun, Jun 10, 2012 at 07:50:07PM +0300, Michael S. Tsirkin wrote:
> On Sun, Jun 10, 2012 at 06:30:59PM +0200, Jan Kiszka wrote:
> > Caching the host bridge generically means changing all chipsets and,
> > well, also testing that they still work afterward. As explained before,
> > I'd really like to avoid doing this in a single step.
> 
> Surely it is not hard to find a way to switch chipsets gradually.

Just to stress: the problem is that with this patch there
are 2 ways to get routing even for piix.

So instead of your patch which caches just intx route
but always, and which I applied, you could have one that only caches
if the root supplies a new route callback.

Then to set irq, you check cache and if not valid,
fallback on the legacy interface.

With time we convert everyone and drop the legacy interface.

> -- 
> MST