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From: tip-bot for David Woodhouse <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: dwmw2@infradead.org, hpa@zytor.com, mingo@kernel.org,
	tglx@linutronix.de, linux-kernel@vger.kernel.org,
	David.Woodhouse@intel.com
Subject: [tip:irq/core] Document that IRQ_NONE should be returned when IRQ not actually handled
Date: Fri, 30 Oct 2015 02:18:41 -0700	[thread overview]
Message-ID: <tip-d9e4ad5badf4ccbfddee208c898fb8fd0c8836b1@git.kernel.org> (raw)
In-Reply-To: <1446016471.3405.201.camel@infradead.org>

Commit-ID:  d9e4ad5badf4ccbfddee208c898fb8fd0c8836b1
Gitweb:     http://git.kernel.org/tip/d9e4ad5badf4ccbfddee208c898fb8fd0c8836b1
Author:     David Woodhouse <dwmw2@infradead.org>
AuthorDate: Wed, 28 Oct 2015 16:14:31 +0900
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Fri, 30 Oct 2015 10:13:26 +0100

Document that IRQ_NONE should be returned when IRQ not actually handled

Our IRQ storm detection works when an interrupt handler returns
IRQ_NONE for thousands of consecutive interrupts in a second. It
doesn't hurt to occasionally return IRQ_NONE when the interrupt is
actually genuine.

Drivers should only be returning IRQ_HANDLED if they have actually
*done* something to stop an interrupt from happening — it doesn't just
mean "this really *was* my device".

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: davem@davemloft.net
Link: http://lkml.kernel.org/r/1446016471.3405.201.camel@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/irqreturn.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/irqreturn.h b/include/linux/irqreturn.h
index e374e36..eb1bdcf 100644
--- a/include/linux/irqreturn.h
+++ b/include/linux/irqreturn.h
@@ -3,7 +3,7 @@
 
 /**
  * enum irqreturn
- * @IRQ_NONE		interrupt was not from this device
+ * @IRQ_NONE		interrupt was not from this device or was not handled
  * @IRQ_HANDLED		interrupt was handled by this device
  * @IRQ_WAKE_THREAD	handler requests to wake the handler thread
  */

      reply	other threads:[~2015-10-30  9:19 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-28  7:14 [PATCH] Document that IRQ_NONE should be returned when IRQ not actually *handled* David Woodhouse
2015-10-30  9:18 ` tip-bot for David Woodhouse [this message]

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