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Date: Tue, 16 Jun 2009 20:37:23 +0300
From: Gleb Natapov <gleb@redhat.com>
Subject: Re: [Qemu-devel] [PATCH] Register usb-uhci reset function.
Message-ID: <20090616173723.GF782@redhat.com>
References: <20090616124702.GS19508@redhat.com>
	<200906161814.58491.paul@codesourcery.com>
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To: Paul Brook <paul@codesourcery.com>
Cc: qemu-devel@nongnu.org

On Tue, Jun 16, 2009 at 06:14:57PM +0100, Paul Brook wrote:
> On Tuesday 16 June 2009, Gleb Natapov wrote:
> > Update irq line on reset. Reseting irq line is required because
> > racing irq from pci device will call piix3_set_irq(). piix3_set_irq()
> > will remember current level in pci_irq_levels[]. The PIC line will be
> > triggered if one of pci_irq_levels[] is set (depends on piix3 config).
> > If for instance pci_irq_levels[0] and pci_irq_levels[1] are mapped to
> > the same PIC irq and during reset pci_irq_levels[1] == 1, but device
> > that drives pci_irq_levels[0] is initialized first the device driver
> > will not be able to lower irq line.
> 
> This is nonsense.
> 
The writeup below is nonsense. I described you circumstances. Show me
the code where it works different from what I described.

> The only relevant circumstances are if the devices raises an IRQ, and is then 
> reset by software while the system is running. It's got nothing to do with 
> piix3, PCI bus interrupt sharing or system reset. If you are seeing problems 
> after a system reset then your bug lies elsewhere.
> 
So you apparently never heard about hardware reset? You never saw buggy
guests that does not reset HW before reboot?

--
			Gleb.