From b39898cd4077f4b6ec706e717c938751c34e1dc4 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 6 Nov 2013 12:30:07 +0100 Subject: genirq: Prevent spurious detection for unconditionally polled interrupts On a 68k platform a couple of interrupts are demultiplexed and "polled" from a top level interrupt. Unfortunately there is no way to determine which of the sub interrupts raised the top level interrupt, so all of the demultiplexed interrupt handlers need to be invoked. Given a high enough frequency this can trigger the spurious interrupt detection mechanism, if one of the demultiplex interrupts returns IRQ_NONE continuously. But this is a false positive as the polling causes this behaviour and not buggy hardware/software. Introduce IRQ_POLLED which can be set at interrupt chip setup time via irq_set_status_flags(). The flag excludes the interrupt from the spurious detector and from all core polling activities. Reported-and-tested-by: Michael Schmitz Cc: Geert Uytterhoeven Cc: linux-m68k@vger.kernel.org Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1311061149250.23353@ionos.tec.linutronix.de --- include/linux/irq.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'include/linux/irq.h') diff --git a/include/linux/irq.h b/include/linux/irq.h index 56bb0dc8b7d4..7dc10036eff5 100644 --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -70,6 +70,9 @@ typedef void (*irq_preflow_handler_t)(struct irq_data *data); * IRQ_MOVE_PCNTXT - Interrupt can be migrated from process context * IRQ_NESTED_TRHEAD - Interrupt nests into another thread * IRQ_PER_CPU_DEVID - Dev_id is a per-cpu variable + * IRQ_IS_POLLED - Always polled by another interrupt. Exclude + * it from the spurious interrupt detection + * mechanism and from core side polling. */ enum { IRQ_TYPE_NONE = 0x00000000, @@ -94,12 +97,14 @@ enum { IRQ_NESTED_THREAD = (1 << 15), IRQ_NOTHREAD = (1 << 16), IRQ_PER_CPU_DEVID = (1 << 17), + IRQ_IS_POLLED = (1 << 18), }; #define IRQF_MODIFY_MASK \ (IRQ_TYPE_SENSE_MASK | IRQ_NOPROBE | IRQ_NOREQUEST | \ IRQ_NOAUTOEN | IRQ_MOVE_PCNTXT | IRQ_LEVEL | IRQ_NO_BALANCING | \ - IRQ_PER_CPU | IRQ_NESTED_THREAD | IRQ_NOTHREAD | IRQ_PER_CPU_DEVID) + IRQ_PER_CPU | IRQ_NESTED_THREAD | IRQ_NOTHREAD | IRQ_PER_CPU_DEVID | \ + IRQ_IS_POLLED) #define IRQ_NO_BALANCING_MASK (IRQ_PER_CPU | IRQ_NO_BALANCING) -- cgit v1.2.3