Hi Konrad,
	Thanks for testing the patch set! After analyzing the log
files, I feel something is wrong with the Radeon driver. With good
configuration, IRQ18 is shared by OHCI controllers and Radeon GPU
card. With bad configuration, only OHCI controllers are bound to
IRQ18. Radeon GPU card may have been bound to another wrong IRQ,
which then causes the interrupt storm.
	But I have no hardware available to verify the hypothesis,
so could you please help to apply the attached patch and run the
test again?
	Thanks!
	Gerry

On 2014/7/15 3:41, Konrad Rzeszutek Wilk wrote:
> On Mon, Jul 14, 2014 at 01:26:42PM -0400, Konrad Rzeszutek Wilk wrote:
>> On Wed, Jun 25, 2014 at 04:40:31PM +0800, Jiang Liu wrote:
>>> This patch set enhances IOAPIC core and ACPI drivers to support IOAPIC
>>> hotplug on x86 platforms. It's based on tip/x86/apic.
>>>
>>> You may pull it from 
>>> https://github.com/jiangliu/linux.git ioapic/hotplug_v3
>>
>> With this patchset (on top of 3.16-rc5) my USB driver gets notified
>> it has interrupts but it thinks it does not have to acknowledge any.
>> I can only reproduce this under a 32-bit arch so far.
>>
>> Please see the good.log and the bad.log 
> 
> tglx asked for apic=debug on the line, so here they are again with
> those parameters.
> 
> Please note that the 'good.log' this time is
>  3.16-rc6 + tip/master + tip/x86/apic
> 
> And 'bad.log' is:
> 
>  3.16-rc6 + tip/master + tip/x86/apic + ioapic/hotplug_v3
>