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Re: [Qemu-devel] Register uhci_reset() callback.
From: |
Blue Swirl |
Subject: |
Re: [Qemu-devel] Register uhci_reset() callback. |
Date: |
Tue, 16 Jun 2009 18:14:51 +0300 |
On 6/15/09, Gleb Natapov <address@hidden> wrote:
> On Mon, Jun 15, 2009 at 10:50:04PM +0300, Blue Swirl wrote:
> > On 6/15/09, Gleb Natapov <address@hidden> wrote:
> > > On Mon, Jun 15, 2009 at 09:57:54PM +0300, Blue Swirl wrote:
> > > > On 6/15/09, Gleb Natapov <address@hidden> wrote:
> > > > > On Mon, Jun 15, 2009 at 06:56:26PM +0100, Paul Brook wrote:
> > > > > > > May be, but in this case after previous patch to reset
> interrupt level
> > > > > > > for each device at PCI bridge level was rejected on the
> premise that
> > > > > > > device should lower its own irq line on reset and since
> patches started
> > > > > > > flowing in to do just that, I did not expect that eloquent
> explanation
> > > > > > > would be needed for such trivial and obviously correct change.
> > > > > >
> > > > > > This argument makes no sense. The fact that you'd recently
> submitted very
> > > > > > similar looking patches which either got rejected or need
> modification is a
> > > > > > good argument for providing an explanation. How else are we
> supposed to know
> > > > > > that you're not just making the same mistake again?
> > > > >
> > > > > They was not even "similar looking". Have you followed the
> discussion
> > > > > that those patches generated? Look at this commit and especially
> its commit
> > > > > message: 32c86e95b. This commit is a direct result of the
> discussion
> > > > > previous patches generated. Look at my patch now. Looks similar,
> no? So
> > > > > people with commit permissions can follow lower standards that we
> mere
> > > > > mortals?
> > > >
> > > > I find nothing wrong with your commit message (for completeness, it
> > > > could mention that it installs a reset handler).
> > > >
> > >
> > > It does in subject line. Subject line goes to log message with git-am.
> > >
> > >
> > > > Maybe lowering the irq should actually be unnecessary, qemu_irq is not
> > > > equal to hardware interrupt line.
> > >
> > > 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 will not
> > > be able to lower irq line.
> >
> > Maybe, but then the other device is reset also piix3 at some point.
>
> Because interrupt line is stuck a guest can't get to the point where it
> loads a driver to the second device. For outside observer the guest
> just hangs.
I see. The problem is in piix_pci interrupt handling, pci_irq_levels[]
should be set to zero on reset.
- Re: [Qemu-devel] Register uhci_reset() callback., (continued)
- Re: [Qemu-devel] Register uhci_reset() callback., Paul Brook, 2009/06/15
- Re: [Qemu-devel] Register uhci_reset() callback., Gleb Natapov, 2009/06/15
- Re: [Qemu-devel] Register uhci_reset() callback., Blue Swirl, 2009/06/15
- Re: [Qemu-devel] Register uhci_reset() callback., Gleb Natapov, 2009/06/15
- Re: [Qemu-devel] Register uhci_reset() callback., Blue Swirl, 2009/06/15
- Re: [Qemu-devel] Register uhci_reset() callback., Gleb Natapov, 2009/06/15
- Re: [Qemu-devel] Register uhci_reset() callback.,
Blue Swirl <=
- Re: [Qemu-devel] Register uhci_reset() callback., Gleb Natapov, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Blue Swirl, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Gleb Natapov, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Blue Swirl, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Gleb Natapov, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Avi Kivity, 2009/06/18
- Re: [Qemu-devel] Register uhci_reset() callback., Paul Brook, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Blue Swirl, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Paul Brook, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Blue Swirl, 2009/06/16