[Qemu-devel] Re: [PATCH 8/8] ahci: fix !msi interrupts

[Alexander Graf]

Jan Kiszka wrote:
> On 2011-01-17 17:00, Alexander Graf wrote:
>   
>> Jan Kiszka wrote:
>>     
>>> On 2010-12-20 22:13, Alexander Graf wrote:
>>>   
>>>       
>>>> When not using MSI, receiving an interrupt while the interrupt line is 
>>>> active
>>>> pulses the interrupt line. Without this, guests don't realize that a new
>>>> interrupt occured.
>>>>     
>>>>         
>>> This doesn't look OK. The device model should look at the currently used
>>> mode and switch between edge and level triggering accordingly. As it
>>> appears like this is what it already does, this change may just paper
>>> over the real issue.
>>>   
>>>       
>> Well, I have this internal abstraction to make edge and level triggered
>> interrupt triggering easier. irq_lower is a simple nop for the edge case.
>>
>>     
>
> I'm concerned about the artificial edge you generate for the level
> triggered case. That's not like real hw behaves. If you need it,
> something else might still be broken.
>   

Hrm. So worst case we generate a spurious interrupt?


Alex