On Thu, Aug 5, 2021 at 1:26 PM Viresh Kumar via Stratos-dev stratos-dev@op-lists.linaro.org wrote:
On 03-08-21, 17:01, Arnd Bergmann wrote:
As far as I can tell, the update_irq_type() message would lead to the interrupt getting delivered when it was armed and is now getting disabled, but I don't see why we would call update_irq_type() as a result of the eventq notification.
Based on discussion we had today (offline), I changed the design a bit and used handle_level_irq() instead, as it provides consistent calls to mask/unmask(), which simplified the whole thing a bit.
The new flow looks much nicer to me, without the workqueue, and doing the requeue directly in the unmask() operation.
I don't quite understand the purpose of the type_pending and mask_pending flags yet, can you explain what they actually do?
Also, I have no idea about whether using the handle_level_irq() function is actually correct here. I suppose if necessary, the driver could provide its own irq.handler callback in place of that.
Also I have broken the rule from specs, maybe we should update spec with that, where the specs said that the buffer must not be queued before enabling the interrupt. I just queue the buffer unconditionally now from unmask().
I am not sure but there may be some race around the "queued" flag and I wonder if we can land in a scenario where the buffer is left un-queued somehow, while an interrupt is enabled.
Can that be integrated with the "masked" state now? It looks like the two flags are always opposites now.
Arnd