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Re: Legacy PCI interrupt support in PCIe host driver

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On Thu, 16 Mar 2017, Mason wrote:
> About shared ISRs. Are they supposed to return IRQ_HANDLED
> if and only if they handled something?

Every interrupt handler is supposed to return IRQ_NONE if it did not handle
it. That does not depend on shared or not. The handler does not know if
it's on a shared interrupt line or not. IRQF_SHARED only tells, that the
handler is capable of sharing the interrupt line with another device.

> Will that stop the next ISR from being called?

No.

> I guess if two interrupts fire at the same time, we'll just take two
> separate exceptions?

Wrong guess. That might work with level interupts, but with other types
nothing will raise another exception. Sharing interrupts on edge types is a
stupid idea, but hardware folks insist on implementing stupid ideas.

Thanks,

	tglx

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Thread

Legacy PCI interrupt support in PCIe host driver Mason <slash.tmp@free.fr> - 2017-03-16 16:50 +0100
  Re: Legacy PCI interrupt support in PCIe host driver Mason <slash.tmp@free.fr> - 2017-03-16 18:40 +0100
    Re: Legacy PCI interrupt support in PCIe host driver Thomas Gleixner <tglx@linutronix.de> - 2017-03-16 18:50 +0100
      Re: Legacy PCI interrupt support in PCIe host driver Mason <slash.tmp@free.fr> - 2017-03-16 20:20 +0100
        Re: Legacy PCI interrupt support in PCIe host driver Thomas Gleixner <tglx@linutronix.de> - 2017-03-16 20:40 +0100

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