Re: [Xen-devel] edge-triggered interrupts in non-ACPI SMP HVM

To:	"He, Qing" <qing.he@xxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject:	Re: [Xen-devel] edge-triggered interrupts in non-ACPI SMP HVM
From:	Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date:	Fri, 27 Oct 2006 10:03:27 +0100
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On 27/10/06 9:30 am, "He, Qing" <qing.he@xxxxxxxxx> wrote:

>> Yes, but why does the guest set only this PCI device's IRQ to
>> edge-triggered? Why not the rtl8139, for example? Neither is explicitly
>> listed in the MP tables, so where does this differing behaviour come from?
>> 
>> -- Keir
> 
> Per my understanding, rtl8139 works fine even if it is edge-triggered, because
> there is no interrupt sharing. So if there is no platform pci device, it is
> possible for guest to set all devices to edge triggered without complaining
> anything. (I do know that if I comment out sanity checks in HV, platform pci
> device works fine in edge triggered mode, and there will be no complaints.)

Oh sorry, I see that check is specific to the platform-device IRQ. I guess
it should be reduced just to a printk warning, and we should work out what
needs adding to the MP tables to get the PCI devices set up with
level-triggering.

 -- Keir



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