Patch "ARM: OMAP2+: INTC: Acknowledge stuck active interrupts" has been added to the 3.4-stable tree

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This is a note to let you know that I've just added the patch titled

    ARM: OMAP2+: INTC: Acknowledge stuck active interrupts

to the 3.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     arm-omap2-intc-acknowledge-stuck-active-interrupts.patch
and it can be found in the queue-3.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From 698b48532539484b012fb7c4176b959d32a17d00 Mon Sep 17 00:00:00 2001
From: Stefan Sørensen <stefan.sorensen@xxxxxxxxxxxxxxx>
Date: Thu, 6 Mar 2014 16:27:15 +0100
Subject: ARM: OMAP2+: INTC: Acknowledge stuck active interrupts
MIME-Version: 1.0
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From: Stefan Sørensen <stefan.sorensen@xxxxxxxxxxxxxxx>

commit 698b48532539484b012fb7c4176b959d32a17d00 upstream.

When an interrupt has become active on the INTC it will stay active
until it is acked, even if masked or de-asserted. The
INTC_PENDING_IRQn registers are however updated and since these are
used by omap_intc_handle_irq to determine which interrupt to handle,
it will never see the active interrupt. This will result in a storm of
useless interrupts that is only stopped when another higher priority
interrupt is asserted.

Fix by sending the INTC an acknowledge if we find no interrupts to
handle.

Signed-off-by: Stefan Sørensen <stefan.sorensen@xxxxxxxxxxxxxxx>
Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/arm/mach-omap2/irq.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/arch/arm/mach-omap2/irq.c
+++ b/arch/arm/mach-omap2/irq.c
@@ -220,6 +220,7 @@ void __init ti81xx_init_irq(void)
 static inline void omap_intc_handle_irq(void __iomem *base_addr, struct pt_regs *regs)
 {
 	u32 irqnr;
+	int handled_irq = 0;
 
 	do {
 		irqnr = readl_relaxed(base_addr + 0x98);
@@ -247,8 +248,15 @@ out:
 		if (irqnr) {
 			irqnr = irq_find_mapping(domain, irqnr);
 			handle_IRQ(irqnr, regs);
+			handled_irq = 1;
 		}
 	} while (irqnr);
+
+	/* If an irq is masked or deasserted while active, we will
+	 * keep ending up here with no irq handled. So remove it from
+	 * the INTC with an ack.*/
+	if (!handled_irq)
+		omap_ack_irq(NULL);
 }
 
 asmlinkage void __exception_irq_entry omap2_intc_handle_irq(struct pt_regs *regs)


Patches currently in stable-queue which might be from stefan.sorensen@xxxxxxxxxxxxxxx are

queue-3.4/arm-omap2-intc-acknowledge-stuck-active-interrupts.patch
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