From: Thomas Gleixner <tglx@linutronix.de>
To: Mason <slash.tmp@free.fr>
Cc: LKML <linux-kernel@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Marc Zyngier <marc.zyngier@arm.com>,
Jason Cooper <jason@lakedaemon.net>,
linux-pci <linux-pci@vger.kernel.org>,
Bjorn Helgaas <helgaas@kernel.org>,
Thibaud Cornic <thibaud_cornic@sigmadesigns.com>,
Phuong Nguyen <phuong_nguyen@sigmadesigns.com>,
Robin Murphy <robin.murphy@arm.com>,
Liviu Dudau <liviu.dudau@arm.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Uwe Kleine-Konig <u.kleine-koenig@pengutronix.de>,
Rob Herring <robh@kernel.org>
Subject: Re: Legacy PCI interrupt support in PCIe host driver
Date: Thu, 16 Mar 2017 18:47:33 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.20.1703161843420.3586@nanos> (raw)
In-Reply-To: <8443b350-6aa6-75f8-af48-892c722fc2d9@free.fr>
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
next prev parent reply other threads:[~2017-03-16 17:48 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-16 15:40 Mason
2017-03-16 17:33 ` Mason
2017-03-16 17:47 ` Thomas Gleixner [this message]
2017-03-16 19:13 ` Mason
2017-03-16 19:36 ` Thomas Gleixner
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