Re: [PATCH 2/2] genirq: Resend nested irq's ancestor irq

[Ning Jiang]

2012/6/14 Thomas Gleixner <tglx@xxxxxxxxxxxxx>:
> On Thu, 14 Jun 2012, Ning Jiang wrote:
>> We'll set IRQS_PENDING for handle_nested_irq if it's disabled. When
>> it's re-enabled later on, check_irq_resend() will detect this flag
>> and trigger the software resend mechanism. resend_irqs() will call
>> desc->handle_irq() directly to process this interrupt, hence the
>> irq_nested_primary_handler() will be called for the nested irq which
>> gives us a warning.
>>
>> If we need to resend a nested interrupt, we have to trace all the
>> way back to its ancestor and trigger ancestor's irq flow handler.
>
> And what makes you believe that the ancestors demux handler will find
> the irq bit of the nested interrupt still pending? There is NO
> guarantee for that.

You are right.

> The correct solution for this is to replace the tasklet with a kernel
> thread and check whether the interrupt is marked nested or not and
> then invoke the correct function.
>

Do you want something like this? This just gives a rough idea. Please
help to review.