Re: [Qemu-devel] [PATCH] virtio-pci: Clear IRQ at reset

[Peter Maydell]

On 12 March 2015 at 10:16, Michael S. Tsirkin <address@hidden> wrote:
> So thinking about this more, by the time kdump tries to reset device,
> linux has probably already disabled the IRQ at the APIC level.
> Isn't that the case? If so, the patch won't help, will it?

Trying to deassert (or worse, assert) interrupt lines in
device reset functions is slightly bogus, yes. In general
the theory is that the interrupt controller the interrupt line
is connected to should have its own reset handling which
treats the line as going back to deasserted, because there's
no guarantee made about which of the two ends of the line
gets its reset handler called first.

Things are not really this neat in practice though. (There's
no good way to model a device which comes out of reset with
a line asserted, for instance.)

-- PMM