Commit 698b4853 authored Mar 06, 2014 by Stefan Sørensen Committed by Tony Lindgren Mar 13, 2014

ARM: OMAP2+: INTC: Acknowledge stuck active interrupts



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.

Cc: stable@vger.kernel.org
Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

parent cfbf8d48

arch/arm/mach-omap2/irq.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -222,6 +222,7 @@ 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);
		@@ -249,8 +250,15 @@ 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)

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